Scope down GitHub token permissions for lint-ruby.yml

Author: AdnaneKhan

.github/workflows/lint-ruby.yml

@@ -4,6 +4,10 @@ on:  # yamllint disable-line rule:truthy
   pull_request:
   workflow_dispatch:
 
+
+permissions:
+  contents: read
+
 jobs:
   rubocop:
     name: RuboCop