Add permissions to workflow

Author: jonashellmann

.github/workflows/ruby.yml

@@ -1,12 +1,10 @@
 name: Ruby
-
 on: [push, pull_request]
-
+permissions:
+  contents: read
 jobs:
   test:
-
     runs-on: ubuntu-latest
-
     steps:
     - uses: actions/[email protected]
     - name: Set up Ruby