[gnome-shell-extensions] ci: Add back commit-rules file

[Florian Müllner <fmuellner src gnome org>]

commit dcd5dc4c7f036209af04924e0a1c6e86fdac31b9
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Jan 11 14:16:03 2021 +0100

    ci: Add back commit-rules file
    
    Somehow git-mv ended up as git-rm without me noticing, whoops.

 .gitlab-ci/commit-rules.yml | 13 +++++++++++++
 1 file changed, 13 insertions(+)
---
diff --git a/.gitlab-ci/commit-rules.yml b/.gitlab-ci/commit-rules.yml
new file mode 100644
index 0000000..a3913a9
--- /dev/null
+++ b/.gitlab-ci/commit-rules.yml
@@ -0,0 +1,13 @@
+patterns:
+  deny:
+    - regex: '^$CI_MERGE_REQUEST_PROJECT_URL/(-/)?merge_requests/$CI_MERGE_REQUEST_IID$'
+      message: Commit message must not contain a link to its own merge request
+    - regex: '^extensions/'
+      message: Commit message subject should not be prefixed with 'extensions/', use the extension name 
instead
+      where: subject
+    - regex: '^[^:]+: [a-z]'
+      message: "Commit message subject should be properly Capitalized. E.g.  'window: Marginalize 
extradicity'"
+      where: subject
+    - regex: '^\S*\.js:'
+      message: Commit message subject prefix should not include .js
+      where: subject