Add danger (#956)

* Add danger. closes #955

* Do not check ToC

* Update CHANGELOG

* Fix missing period for CHANGELOG

* Fix contribution lines

* Update CHANGELOG date format

* Align ToC

---------

Co-authored-by: Daniel (dB.) Doubrovkine <dblock@dblock.org>

Author: numbata

.github/workflows/danger.yml

@@ -0,0 +1,22 @@
+---
+name: danger
+on: pull_request
+
+jobs:
+  danger:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 100
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 3.4
+        bundler-cache: true
+    - name: Run Danger
+      run: |
+        # the token is public, has public_repo scope and belongs to the grape-bot user owned by @dblock, this is ok
+        TOKEN=$(echo -n Z2hwX2lYb0dPNXNyejYzOFJyaTV3QUxUdkNiS1dtblFwZTFuRXpmMwo= | base64 --decode)
+        DANGER_GITHUB_API_TOKEN=$TOKEN bundle exec danger --verbose
+