Declare permissions

Repositories can be configured with Default access (restricted)
https://docs.github.com/en/actions/security-guides/automatic-token-authentication#permissions-for-the-github_token

Best practice says that workflows should declare the minimal permissions they require.
Without declaring permissions, paranoid forks fail miserably.

.github/workflows/csv-coverage-timeseries.yml

@@ -3,6 +3,9 @@ name: Build framework coverage timeseries reports
 on:
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest