Tighten security on code-path-changes workflow (#4193)

Author: bretg

.github/workflows/code-path-changes.yml

@@ -14,6 +14,9 @@ env:
   GITHUB_PR_NUMBER: ${{ github.event.pull_request.number }}
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
+permissions:
+  contents: read
+
 jobs:
   notify:
     runs-on: ubuntu-latest