build: harden ci.yml permissions

Signed-off-by: Alex <aleksandrosansan@gmail.com>

.github/workflows/ci.yml

@@ -4,6 +4,9 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
 jobs:
   inspect-code:
     name: Code Quality