ci: pass Codecov token as environment variable

Passing it as an input does not seem to work in workflow_calls for unknown
reasons. [1] Instead we try to pass it as an environment variable what is also
possible according to the action documentation. [2]

[1] codecov/codecov-action#1292 (comment)
[2] https://github.com/codecov/codecov-action/blob/54bcd87/README.md#usage

.github/workflows/test.yml

@@ -60,7 +60,8 @@ jobs:
  uses: codecov/codecov-action@v4
  if: github.repository == 'winft/como' || github.event_name == 'pull_request'
  with:
- token: ${{ secrets.CODECOV_TOKEN }}
  file: coverage.xml
  fail_ci_if_error: true
  verbose: true
+ env:
+ CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}