Include a basic pre-commit configuration

[nicois]

This adds a very simple pre-commit configuration. It will make it easier for contributers to verify their code is correctly formatted before pushing.

This initial version simply executed yapf, mypy and pylint.

[codecov[bot]]

Codecov Report

Merging #536 (d1c43e8) into main (65f57f6) will decrease coverage by 0.00%. The diff coverage is 84.79%.

@@            Coverage Diff             @@
##             main     #536      +/-   ##
==========================================
- Coverage   89.42%   89.41%   -0.01%     
==========================================
  Files          29       29              
  Lines        4490     4487       -3     
==========================================
- Hits         4015     4012       -3     
  Misses        475      475              

Impacted Files	Coverage Δ
version.py	100.00% <ø> (ø)
pghoard/logutil.py	64.00% <50.00%> (-1.39%)	:arrow_down:
pghoard/gnutaremu.py	82.38% <69.23%> (ø)
pghoard/basebackup_delta.py	78.32% <72.22%> (ø)
pghoard/basebackup.py	84.95% <74.57%> (ø)
pghoard/webserver.py	89.83% <80.39%> (+0.70%)	:arrow_up:
pghoard/compressor.py	92.64% <81.25%> (ø)
pghoard/config.py	92.07% <84.61%> (ø)
pghoard/archive_cleanup.py	92.30% <85.71%> (ø)
pghoard/pghoard.py	82.63% <86.11%> (-0.17%)	:arrow_down:
... and 18 more

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[nicois]

isort and yapf are mutually incompatible, as the changes made by one conflict with the other. Given many files needed to be reformatted either way, I have taken the liberty of using a different import sorter, which I find provides for cleaner diffs (and cherry-picks).

[kmichel-aiven]

isort and yapf are mutually incompatible, as the changes made by one conflict with the other. Given many files needed to be reformatted either way, I have taken the liberty of using a different import sorter, which I find provides for cleaner diffs (and cherry-picks).

I'd rather not introduce difference with other repositories we have, where we settled on isort/black (which are compatible): https://github.com/aiven/rohmu/pull/51/commits/ec0feb3ad35b08ce543332de4eaf0b7e40324d23 https://github.com/aiven/myhoard/pull/84/commits/489cf959c12633cd8c1d765c5223625272b35ddf + https://github.com/aiven/myhoard/pull/84/commits/d99b99880e64e1e60ab115d2d2e6badd9d9a7346

[nicois]

ok, updated to use black. I can rebase this when other major PRs are merged, to reduce the need to reformat works in progress.

[Ormod]

Would be a good improvement but the PR conflicts badly so closing this one, please reopen if you want to come back to this.