message: use nightly image in coverage
diff: @@ -10,7 +10,7 @@ jobs:
  name: coverage
  runs-on: ubuntu-latest
  container:
  - image: xd009642/tarpaulin
  + image: xd009642/tarpaulin:develop-nightly
  options: --security-opt seccomp=unconfined
  steps:
  - name: Checkout repository
  