Improve changelog validation

* Cleanup versions in changelog
* Refactor changelog to validate. Use nested lists for contents of each version.
* Fix internal link in changelog
* Refactor action to use 2 jobs

Author: waylan

.github/workflows/changelog-validator.yml

@@ -7,14 +7,41 @@ on:
     - 'docs/changelog.md'
 
 jobs:
-  validate:
+  validate-unreleased:
+    # Validates changelog and confirms that an Unreleased entry exists.
+    # Only run when the `release` label is not set on a PR.
+    if: ${{ ! contains(github.event.pull_request.labels.*.name, 'release') }}
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Validate Changelog
+      id: changelog_reader
+      uses: mindsers/changelog-reader-action@v2
+      with:
+        validation_level: error
+        path: docs/changelog.md
+        version: Unreleased
 
+  validate-release:
+    # Validates changelog and confirms an entry exists for version in code.
+    # Only run when the `release` label is set on a PR.
+    if: ${{ contains(github.event.pull_request.labels.*.name, 'release') }}
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.11
+    - name: Install Markdown
+      run: python -m pip install semver .
+    - name: Get Markdown Version
+      id: markdown
+      run: echo "version=$(python -c 'import markdown, semver; print(semver.Version.parse(markdown.__version__, optional_minor_and_patch=True))')" >> $GITHUB_OUTPUT
     - name: Validate Changelog
       id: changelog_reader
       uses: mindsers/changelog-reader-action@v2
       with:
         validation_level: error
         path: docs/changelog.md
+        version: ${{ steps.markdown.outputs.version }}