add a workflow to generate changeset feedback on PRs

.github/workflows/automate_changeset_feedback.yml

@@ -0,0 +1,48 @@
+name: Automate changeset feedback
+on:
+  pull_request_target:
+    branches: ['main']
+
+permissions:
+  pull-requests: write
+  actions: none
+  checks: none
+  contents: none
+  deployments: none
+  issues: none
+  packages: none
+  pages: none
+  repository-projects: none
+  security-events: none
+  statuses: none
+
+jobs:
+  changeset-feedback:
+    name: Generate Changeset Feedback
+    # prevent running towards forks and version packages
+    if: github.repository == 'redhat-developer/rhdh-plugins' && github.event.pull_request.user.login != 'rhdh-bot'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@63c24ba6bd7ba022e95695ff85de572c04a18142 # v2.7.0
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@1d96c772d19495a3b5c517cd2bc0cb401ea0529f # v4.1.3
+        with:
+          # Fetch the commit that's merged into the base rather than the target ref
+          # This will let us diff only the contents of the PR, without fetching more history
+          ref: 'refs/pull/${{ github.event.pull_request.number }}/merge'
+      - name: fetch base
+        run: git fetch --depth 1 origin ${{ github.base_ref }}
+
+      - uses: backstage/actions/[email protected]
+        name: Generate feedback
+        with:
+          diff-ref: 'origin/main'
+          marker: <!-- changeset-feedback -->
+          issue-number: ${{ github.event.pull_request.number }}
+          app-id: ${{ secrets.RHDH_GH_APP_ID }}
+          private-key: ${{ secrets.RHDH_GH_APP_PRIVATE_KEY }}
+          installation-id: ${{ secrets.RHDH_GH_APP_INSTALLATION_ID }}
+          multiple-workspaces: true