ci: ensure PR subjects follow semantic commit spec (#2096)

Author: gegoune

.github/workflows/semantic-pr-subject.yml

@@ -0,0 +1,15 @@
+name: Semantic Pull Request Subject
+on:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - edited
+      - synchronize
+jobs:
+  semantic-pr-subject:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: amannn/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}