reinstate .coveragerc

[bjlittle]

This PR reinstates the .coveragerc file that I accidentally on purpose purged in #41 ☺️

Hopefully this will reinstate codecov test coverage metrics of cython .pyx files 🤞

[codecov]

Codecov Report

Merging #43 (4d2b562) into master (6248316) will decrease coverage by 1.77%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #43      +/-   ##
==========================================
- Coverage   98.33%   96.56%   -1.78%     
==========================================
  Files           5        4       -1     
  Lines         480      320     -160     
  Branches        0        6       +6     
==========================================
- Hits          472      309     -163     
- Misses          8       11       +3     

Impacted Files	Coverage Δ
stratify/tests/test_bounded_vinterp.py
stratify/tests/performance.py
stratify/tests/test_vinterp.py
stratify/_vinterp.pyx	95.29% <0.00%> (ø)
stratify/_conservative.pyx	100.00% <0.00%> (ø)

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[bjlittle]

Bingo 🎉 ... of course codecov is triggering a PR failure as its deemed coverage has regressed, but that's based on an unfair comparison i.e., previously .pyx files weren't included in its metrics and it's also excluding files that shouldn't have been included i.e., the tests themselves.

[bjlittle]

I may now play with configuring codecov, rather than opting for the default behaviours...

[bjlittle]

Closes #42

[bjlittle]

@jamesp Are you happy to roll with this PR as is? I think it's good to go 👍