feat: add `block-unconventional-commits` workflow

Signed-off-by: John Molakvoæ <skjnldsv@users.noreply.github.com>

.github/workflows/block-unconventional-commits.yml

@@ -0,0 +1,31 @@
+# This workflow is provided via the organization template repository
+#
+# https://github.com/nextcloud/.github
+# https://docs.github.com/en/actions/learn-github-actions/sharing-workflows-with-your-organization
+
+name: Block unconventional commits
+
+on:
+  pull_request:
+    types: [opened, ready_for_review, reopened, synchronize]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: block-unconventional-commits-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  block-unconventional-commits:
+    name: Block unconventional commits
+
+    runs-on: ubuntu-latest-low
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+
+      - uses: webiny/action-conventional-commits@8bc41ff4e7d423d56fa4905f6ff79209a78776c7 # v1.3.0
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}