ci: ensure PR titles adhere to conventional commits (#203)

.github/workflows/repo--validate-pr-title.yml

@@ -0,0 +1,27 @@
+name: Validate PR Title
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - edited
+      - synchronize
+  push:
+    branches:
+      - release-please-* # Trigger for release-please PRs, but skip the job
+  merge_group: # Trigger in the merge queue, but skip the job
+
+jobs:
+  validate-pr-title:
+    if: github.event_name == 'pull_request_target'
+    runs-on: [taiko-runner]
+    steps:
+      - uses: amannn/action-semantic-pull-request@v5
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          subjectPattern: ^(?![A-Z])(?!.*\btypo\b).+$ # Require lowercase PR title and prohibit word "typo"
+          subjectPatternError: |
+            The subject "{subject}" found in the pull request title "{title}"
+            didn't match the configured pattern. Please ensure that the subject
+            doesn't start with an uppercase character and doesn't contain the word "typo".