update github workflow to write changelog

.github/workflows/release.yml

@@ -57,6 +57,19 @@ jobs:
           NEXT_VERSION="v${VERSION_PARTS[0]}.${VERSION_PARTS[1]}.${VERSION_PARTS[2]}"
           echo ::set-output name=NEXT_VERSION::"$NEXT_VERSION"
 
+      - name: Update CHANGELOG.md
+        run: |
+          echo "## [${{ steps.nextversion.outputs.NEXT_VERSION }}]" >> CHANGELOG.md
+          echo "- ${{ github.event.pull_request.title }}" >> CHANGELOG.md
+
+      - name: Commit changes
+        run: |
+          git add CHANGELOG.md
+          git commit -m "Update CHANGELOG.md for PR #${{ github.event.pull_request.number }}"
+
+      - name: Push changes
+        run: git push origin HEAD:master
+
       - name: Create and publish new tag
         run: |
           git tag ${{ steps.nextversion.outputs.NEXT_VERSION }}