ci: Enforce compliance check at pr_target

Behavior with approving and unlabeling was not preferable.
Now this will run on pr_target - meaning as soon as PR
is introduced for the repository.

This might also help with review process, as contributor
will know right away about any style issues.

Author: szymon-czapracki

.github/workflows/compliance_check.yml

@@ -20,8 +20,8 @@
 name: Compliance check
 
 on:
-  pull_request:
-    types: [opened, synchronize, reopened, labeled, unlabeled]
+  pull_request_target:
+    types: [opened, synchronize, reopened, synchronize]
 
 jobs:
   style_check: