chore: GH workflow permissions (#25)

Signed-off-by: Jan Kowalleck <jan.kowalleck@gmail.com>

Author: jkowalleck

.github/workflows/test.yml

@@ -13,6 +13,9 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+# see https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/controlling-permissions-for-github_token
+permissions: {}
+
 jobs:
   # unit tests
   # units: