Merge branch '24276-usernames-with-dots' into 'master'

Allow registering users where the username contains dots (.)

## What does this MR do?

- Allow registering users whose usernames contains dots `.`
- This can currently be done by registering with a username containing no dots, and then editing the username to have dots in the user's profile settings.

## Does this MR meet the acceptance criteria?

-  [#24276/!7500] Unable to register names with dot
    - [x]  Implementation
    - [x]  Tests
        - [x]  Added
        - [x]  [Passing](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7500/builds)
    - [x]  Meta
        - [x]  CHANGELOG entry created
        - [x]  Documentation created/updated
        - [x]  API support added
        - [x]  Branch has no merge conflicts with `master`
        - [x]  Squashed related commits together
    - [x]  Review
        - [x]  Endboss
            - [x]  Use `Gitlab::Regex::NAMESPACE_REGEX_STR` instead of a hardcoded pattern
            - [x]  Define `NAMESPACE_REGEX_STR` in terms of `NAMESPACE_REGEX_STR_JS`
    - [ ]  Wait for merge


## What are the relevant issue numbers?

- Closes #24276

See merge request !7500

1 files changed, 4 insertions, 0 deletions

diff --git a/changelogs/unreleased/24276-usernames-with-dots.yml b/changelogs/unreleased/24276-usernames-with-dots.yml
new file mode 100644
index 00000000000..9aeeb33e9ef
--- /dev/null
+++ b/changelogs/unreleased/24276-usernames-with-dots.yml
@@ -0,0 +1,4 @@
+---
+title: Allow registering users whose username contains dots
+merge_request: 7500
+author: Timothy Andrew