CodeCov warning

[Pytlicek]

Fix issue with CodeCov:

->  Issue detecting commit SHA. Please run actions/checkout with fetch-depth > 1 or set to 0
    current dir:  /home/runner/work/fastapi-featureflags/fastapi-featureflags
    project root: .
    Yaml not found, that's ok! Learn more at http://docs.codecov.io/docs/codecov-yaml
==> Running gcov in . (disable via -X gcov)
==> Python coveragepy not found
==> Searching for coverage reports in:
    + .
--> No coverage report found.
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