`codecov` PyPI package removed as deprecated

[adamgranthendry]

Issue

codecov was removed from PyPI as deprecated, but scooby's requirements_test.txt still includes codecov. Thus, pip installing the test dependencies fails.

Also, for those using poetry, installing with poetry add fails since poetry requires all dependencies to be compatible with each other and resolvable during install regardless of whether they are required for install. Hence, using poetry add scooby results in the error Package codecov (2.1.12) not found..

Recommendation

Per the deprecation guide:

1. Remove codecov from requirements_test.txt
2. Replace any calls to Codecov with the new Codecov Uploader
3. If you are using coveragepy to collect code coverage, you will need to add

      coverage xml

   before calling the new uploader.

NOTE: Version 2.1.13, but not 2.1.12, was reinstated to PyPI see post-mortem message 1 and 2, but it appears all language-specific uploaders will eventually be deprecated (they haven't released the schedule yet, AFAIK). Using 2.1.13 might be a temporary workaround, but it may be wiser to focus the energy on following the deprecation guide steps instead.

[adamgranthendry]

@banesullivan I noticed coverage status's are off in the coverage.yml. If you just need a diff to appear in PRs, Hynek's article might interest you. It shows how to output an HTML table with coverage to $GITHUB_STEP_SUMMARY.

[banesullivan]

Fixed in #112