Add Contributor Covenant Code of Conduct

This is prompted by @westurner's comments on [rdflib-dev](https://groups.google.com/g/rdflib-dev/c/mdd7rxL9_8I).

The code of conduct is added as markdown so that GitHub recognizes it
(see https://github.com/github/feedback/discussions/9442).

Also:

 - Add myst-parser in docs extras so that we can compile the code of
   conduct into docs.

5 files changed, 137 insertions, 1 deletions

diff --git a/docs/CODE_OF_CONDUCT.md b/docs/CODE_OF_CONDUCT.md
new file mode 100644
index 00000000..23e60458
--- /dev/null
+++ b/docs/CODE_OF_CONDUCT.md
@@ -0,0 +1,133 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our
+community a harassment-free experience for everyone, regardless of age, body
+size, visible or invisible disability, ethnicity, sex characteristics, gender
+identity and expression, level of experience, education, socio-economic status,
+nationality, personal appearance, race, caste, color, religion, or sexual
+identity and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming,
+diverse, inclusive, and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment for our
+community include:
+
+* Demonstrating empathy and kindness toward other people
+* Being respectful of differing opinions, viewpoints, and experiences
+* Giving and gracefully accepting constructive feedback
+* Accepting responsibility and apologizing to those affected by our mistakes,
+  and learning from the experience
+* Focusing on what is best not just for us as individuals, but for the overall
+  community
+
+Examples of unacceptable behavior include:
+
+* The use of sexualized language or imagery, and sexual attention or advances of
+  any kind
+* Trolling, insulting or derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or email address,
+  without their explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Enforcement Responsibilities
+
+Community leaders are responsible for clarifying and enforcing our standards of
+acceptable behavior and will take appropriate and fair corrective action in
+response to any behavior that they deem inappropriate, threatening, offensive,
+or harmful.
+
+Community leaders have the right and responsibility to remove, edit, or reject
+comments, commits, code, wiki edits, issues, and other contributions that are
+not aligned to this Code of Conduct, and will communicate reasons for moderation
+decisions when appropriate.
+
+## Scope
+
+This Code of Conduct applies within all community spaces, and also applies when
+an individual is officially representing the community in public spaces.
+Examples of representing our community include using an official e-mail address,
+posting via an official social media account, or acting as an appointed
+representative at an online or offline event.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported to the community leaders responsible for enforcement at
+https://github.com/RDFLib/rdflib/discussions.
+All complaints will be reviewed and investigated promptly and fairly.
+
+All community leaders are obligated to respect the privacy and security of the
+reporter of any incident.
+
+## Enforcement Guidelines
+
+Community leaders will follow these Community Impact Guidelines in determining
+the consequences for any action they deem in violation of this Code of Conduct:
+
+### 1. Correction
+
+**Community Impact**: Use of inappropriate language or other behavior deemed
+unprofessional or unwelcome in the community.
+
+**Consequence**: A private, written warning from community leaders, providing
+clarity around the nature of the violation and an explanation of why the
+behavior was inappropriate. A public apology may be requested.
+
+### 2. Warning
+
+**Community Impact**: A violation through a single incident or series of
+actions.
+
+**Consequence**: A warning with consequences for continued behavior. No
+interaction with the people involved, including unsolicited interaction with
+those enforcing the Code of Conduct, for a specified period of time. This
+includes avoiding interactions in community spaces as well as external channels
+like social media. Violating these terms may lead to a temporary or permanent
+ban.
+
+### 3. Temporary Ban
+
+**Community Impact**: A serious violation of community standards, including
+sustained inappropriate behavior.
+
+**Consequence**: A temporary ban from any sort of interaction or public
+communication with the community for a specified period of time. No public or
+private interaction with the people involved, including unsolicited interaction
+with those enforcing the Code of Conduct, is allowed during this period.
+Violating these terms may lead to a permanent ban.
+
+### 4. Permanent Ban
+
+**Community Impact**: Demonstrating a pattern of violation of community
+standards, including sustained inappropriate behavior, harassment of an
+individual, or aggression toward or disparagement of classes of individuals.
+
+**Consequence**: A permanent ban from any sort of public interaction within the
+community.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage],
+version 2.1, available at
+[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html][v2.1].
+
+Community Impact Guidelines were inspired by
+[Mozilla's code of conduct enforcement ladder][Mozilla CoC].
+
+For answers to common questions about this code of conduct, see the FAQ at
+[https://www.contributor-covenant.org/faq][FAQ]. Translations are available at
+[https://www.contributor-covenant.org/translations][translations].
+
+[homepage]: https://www.contributor-covenant.org
+[v2.1]: https://www.contributor-covenant.org/version/2/1/code_of_conduct.html
+[Mozilla CoC]: https://github.com/mozilla/diversity
+[FAQ]: https://www.contributor-covenant.org/faq
+[translations]: https://www.contributor-covenant.org/translations
+
diff --git a/docs/conf.py b/docs/conf.py
index d4ae1ae3..6c170963 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -36,6 +36,7 @@ extensions = [
     "sphinx.ext.coverage",
     "sphinx.ext.ifconfig",
     "sphinx.ext.viewcode",
+    "myst_parser",
 ]
 
 apidoc_module_dir = "../rdflib"
diff --git a/docs/index.rst b/docs/index.rst
index 0ebb1741..dfdaf36e 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -83,6 +83,7 @@ For developers
    :maxdepth: 1
 
    developers
+   CODE_OF_CONDUCT
    docs
    persisting_n3_terms
 
diff --git a/requirements.dev.txt b/requirements.dev.txt
index 61ac1626..c2716dd4 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -10,4 +10,5 @@ pytest-cov
 pytest-subtests
 sphinx
 sphinxcontrib-apidoc
+myst-parser
 types-setuptools
diff --git a/setup.py b/setup.py
index f2958959..1c839eed 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@ kwargs["tests_require"] = [
 kwargs["extras_require"] = {
     "html": ["html5lib"],
     "tests": kwargs["tests_require"],
-    "docs": ["sphinx < 5", "sphinxcontrib-apidoc"],
+    "docs": ["sphinx < 5", "sphinxcontrib-apidoc", "myst-parser"],
 }