ci: add friendly pr title message on error (#351)

Signed-off-by: Michael Beemer <[email protected]>

Author: beeme1mr

.github/workflows/pr-lint.yml

@@ -13,11 +13,36 @@ permissions:
 jobs:
   main:
     permissions:
-      pull-requests: read  # for amannn/action-semantic-pull-request to analyze PRs
+      # for amannn/action-semantic-pull-request to analyze PR titles
+      # for marocchino/sticky-pull-request-comment to add comments to the PR
+      pull-requests: write
       statuses: write  # for amannn/action-semantic-pull-request to mark status of analyzed PR
     name: Validate PR title
     runs-on: ubuntu-latest
     steps:
       - uses: amannn/action-semantic-pull-request@v5
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: marocchino/sticky-pull-request-comment@v2
+        # When the previous steps fails, the workflow would stop. By adding this
+        # condition you can continue the execution with the populated error message.
+        if: always() && (steps.lint_pr_title.outputs.error_message != null)
+        with:
+          header: pr-title-lint-error
+          message: |
+            Hey there and thank you for opening this pull request! 👋🏼
+            
+            We require pull request titles to follow the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/) and it looks like your proposed title needs to be adjusted.
+            Details:
+            
+            ```
+            ${{ steps.lint_pr_title.outputs.error_message }}
+            ```
+
+      # Delete a previous comment when the issue has been resolved
+      - if: ${{ steps.lint_pr_title.outputs.error_message == null }}
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:   
+          header: pr-title-lint-error
+          delete: true