ci: add pr-comment workflow

.github/workflows/pr-comment.yml

@@ -0,0 +1,24 @@
+name: Pull request comment after merge
+on:
+  pull_request:
+    types:
+      - closed
+
+jobs:
+  comment:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    env:
+      USERNAME: ${{ github.event.pull_request.user.login }}
+      USER_URL: ${{ github.event.pull_request.user.html_url }}
+    steps:
+      - name: "Comment on the PR"
+        uses: actions/github-script@v6
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: 'Thank you [@${{ env.USERNAME }}](${{ env.USER_URL }}) ❤️\nYour changes has been merged to the `dev` branch. 🎉'
+            })