feat: adding gitlab policy override variables (#335)

* feat: adding override-variables policy

* fix severity and threat

* made title shorter

* change name againnnn

* fix: change name

policies/gitlab/repository.rego

@@ -347,7 +347,7 @@ repository_dismiss_stale_reviews := false {
 
 # METADATA
 # scope: rule
-# title: The ability to override predefined variables should be limited only to users with at least Maintainer role.
+# title: Overriding predefined CI/CD variables should be restricted.
 # description: It’s recommended to restrict users with low privileges from overriding predefined variables, as doing so could compromise the security and integrity of the CI/CD pipeline.
 # custom:
 #   remediationSteps: