Add git add

Author: pmkovar

.github/workflows/generate-release-notes.yml

@@ -66,7 +66,8 @@ jobs:
         run: |
           git config --local user.email "github-actions[bot]@users.noreply.github.com"
           git config --local user.name "github-actions[bot]"
-          git commit -a -m "Add changes"
+          git add release-notes-build/
+          git commit -m "Add changes"
 
       - name: Push HTML and Markdown to release-notes-build branch
         uses: ad-m/github-push-action@v0.8.0