chore(deps): update tj-actions/github-changelog-generator action to v1.21 (#397)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/deploy.yml

@@ -44,7 +44,7 @@ jobs:
           TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
 
       - name: Generate CHANGELOG
-        uses: tj-actions/github-changelog-generator@v1.20
+        uses: tj-actions/github-changelog-generator@v1.21
 
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@v7