feat: add block-unconventional-commits workflow

.github/CONTRIBUTING.md

@@ -29,6 +29,13 @@ Thanks for wanting to contribute source code to Nextcloud. That's great!
 
 Please read the [Developer Manuals][devmanual] to learn how to create your first application or how to test the Nextcloud code with PHPUnit.
 
+### Conventional Commits
+
+Please use [Conventional Commits](https://www.conventionalcommits.org) for your commit messages. This helps maintain clarity and consistency across the project, making it easier to understand changes and automate versioning.
+```
+feat(files_sharing): allow sharing with contacts
+``` 
+
 ### Tests
 
 In order to constantly increase the quality of our software we can no longer accept pull request which submit un-tested code.
@@ -44,9 +51,9 @@ their contribution under the project's license.
 Please read [contribute/developer-certificate-of-origin][dcofile].
 If you can certify it, then just add a line to every git commit message:
 
-````
-  Signed-off-by: Random J Developer <random@developer.example.org>
-````
+```
+Signed-off-by: Random J Developer <random@developer.example.org>
+```
 
 Use your real name (sorry, no pseudonyms or anonymous contributions).
 If you set your `user.name` and `user.email` git configs, you can sign your

.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 }}