Lint the CI configuration and update badge

Using YAML lists over pseudo-JSON lists makes for easier diffs. Breaking
blocks apart with an empty line helps readability. Avoiding strings
delimeters when you don't need them helps with readability. The name of
the workflow should describe its purpose. Multithreading bundle installs
leads to faster builds. And we need to update the badge to our new CI
location.

2 files changed, 33 insertions, 19 deletions

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 014f927..3ddc090 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,63 +1,77 @@
-name: Ruby
+name: CI
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - master
   pull_request:
-    branches: [ master ]
+    branches:
+      - master
 
 jobs:
   danger:
     runs-on: ubuntu-latest
-    if: github.event_name  == 'pull_request'
+    if: ${{ github.event_name == 'pull_request' }}
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-ruby@v1
       with:
-        ruby-version: '2.7'
+        ruby-version: 2.7
     - uses: MeilCli/danger-action@v5
       with:
-        plugins_file: 'Gemfile'
-        install_path: 'vendor/bundle'
-        danger_file: 'Dangerfile'
-        danger_id: 'danger-pr'
+        danger_file: Dangerfile
+        danger_id: danger-pr
+        install_path: vendor/bundle
+        plugins_file: Gemfile
       env:
         DANGER_GITHUB_API_TOKEN: ${{ secrets.github_token }}
+
   test:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        ruby: [2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, head, debug, truffleruby, truffleruby-head]
+        ruby:
+          - 2.7
+          - 2.6
+          - 2.5
+          - 2.4
+          - 2.3
+          - 2.2
+          - 2.1
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
+        ruby-version: ${{ matrix.ruby }}
     - name: Install dependencies
-      run: bundle install
+      run: bundle install --jobs 4 --retry 3
     - name: Run tests
       run: bundle exec rake
+
   test-jruby:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu, macos]
-        jruby: [jruby, jruby-head]
+        os:
+          - macos
+          - ubuntu
+        jruby:
+          - jruby
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: ${{ matrix.jruby }}
         bundler-cache: true
+        ruby-version: ${{ matrix.jruby }}
     - name: Install dependencies
       env:
         JRUBY_OPTS: --debug
-      run: bundle install
+      run: bundle install --jobs 4 --retry 3
     - name: Run tests
       env:
         JRUBY_OPTS: --debug
diff --git a/README.md b/README.md
index 38f7f81..ea38d9f 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 [![Join the chat at https://gitter.im/hashie/hashie](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/hashie/hashie?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Gem Version](http://img.shields.io/gem/v/hashie.svg)](http://badge.fury.io/rb/hashie)
-[![Build Status](http://img.shields.io/travis/hashie/hashie.svg)](https://travis-ci.org/hashie/hashie)
+[![Build Status](https://github.com/hashie/hashie/actions/workflows/main.yml/badge.svg)](https://github.com/hashie/hashie/actions/workflows/main.yml)
 
 [![eierlegende Wollmilchsau](./mascot.svg)](#mascot) Hashie is a growing collection of tools that extend Hashes and make them more useful.