Potential fix for code scanning alert no. 2: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: cinderellasecure

.github/workflows/rubocop.yml

@@ -3,6 +3,8 @@ on:
   pull_request:
     branches:
       - main
+permissions:
+  contents: read
 jobs:
   build:
     runs-on: ubuntu-latest