ci: Use conventional commits-style pull request titles (#3319)

This PR adds a new workflow to CI which will enforce titles to use a
conventional commits-style format.

Author: Mrtenz

.github/workflows/validate-pull-request.yml

@@ -0,0 +1,21 @@
+name: Validate pull request
+on:
+  pull_request:
+    branches:
+      - main
+    types:
+      - edited
+      - opened
+      - reopened
+      - synchronize
+
+jobs:
+  validate-pull-request-title:
+    name: Validate title
+    runs-on: ubuntu-latest
+    steps:
+      - name: Validate title
+        # `amannn/action-semantic-pull-request@v5.4.0`
+        uses: amannn/action-semantic-pull-request@e9fabac35e210fea40ca5b14c0da95a099eff26f
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}