Add codecov token to test workflow

[smokingroosters]

Before submitting

Please complete the following checklist when submitting a PR:

• [ ] All new features must include a unit test. If you've fixed a bug or added code that should be tested, add a test to the tests directory!

• [ ] All new Python code must be clearly commented and documented. If you do make documentation changes, make sure that the docs build and render correctly by running make docs.

• [ ] Ensure that the test suite passes, by running make test.

• [ ] Add a new entry to the .github/CHANGELOG.md file, summarizing the change, and including a link back to the PR.

• [ ] The Walrus source code conforms to PEP8 standards. We check all of our code against Pylint. To lint modified files, simply pip install pylint, and then run pylint thewalrus/path/to/file.py.

When all the above are checked, delete everything above the dashed line and fill in the pull request template.

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Context: Tests were not able to get codecov reports due to change in codecov behaviour, no needing a token even for public repositories

Description of the Change: After adding the token to the repo as a secret, the change allows the worklofw to use the token to properly use codecov

Benefits: Codecov works agian

Possible Drawbacks:

Related GitHub Issues:

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (25b5f08) to head (7704e69). Report is 1 commits behind head on master.

Additional details and impacted files

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