Remove coveralls

[purva-thakre]

coveralls is listed as a dependency in the toml file.

But this package is not compatible with py>3.10.
https://github.com/TheKevJames/coveralls-python#coveralls-for-python

Probably why a warning is raised by pytest in the 3.11 workflow?

https://github.com/vprusso/toqito/actions/runs/6800993611/job/18490827614?pr=212#step:5:668

../../../.cache/pypoetry/virtualenvs/toqito-QfgmswsN-py3.11/lib/python3.11/site-packages/coverage/pytracer.py:223
  /home/runner/.cache/pypoetry/virtualenvs/toqito-QfgmswsN-py3.11/lib/python3.11/site-packages/coverage/pytracer.py:223: DeprecationWarning: currentThread() is deprecated, use current_thread() instead
    self.thread = self.threading.currentThread()

[purva-thakre]

probably related to #218.

[vprusso]

Hmm, I think we can probably remove the coveralls dependencies and usage. It looks like the package isn't well-maintained and hasn't been updated in some time.

Perhaps we can stick with codecov (similarly to how it was done in mitiq?):
unitaryfund/mitiq#301

Any thoughts, @purva-thakre ?

[purva-thakre]

@vprusso I am fine with using codecov. Saves me the work of searching for replacements. thanks!

https://docs.codecov.com/docs#step-1-sign-up-for-codecov