Add github actions CI on Macos

[fizyk]

No description provided.

[coveralls]

Coverage decreased (-0.06%) to 66.061% when pulling 28a13bb on fizyk:ghactions into 9a53f11 on ClearcodeHQ:master.

[coveralls]

Coverage remained the same at 66.116% when pulling 5ac2f32 on fizyk:ghactions into ff9c823 on ClearcodeHQ:master.

[codecov-io]

Codecov Report

Merging #382 (6044532) into master (cafaa30) will increase coverage by 2.19%.
The diff coverage is 78.37%.

@@            Coverage Diff             @@
##           master     #382      +/-   ##
==========================================
+ Coverage   64.92%   67.12%   +2.19%     
==========================================
  Files          14       15       +1     
  Lines         499      508       +9     
==========================================
+ Hits          324      341      +17     
+ Misses        175      167       -8     

Flag	Coverage Δ
unittests	67.12% <78.37%> (+2.19%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tests/test_postgresql.py	86.95% <60.00%> (+18.10%)	⬆️
src/pytest_postgresql/retry.py	70.58% <70.58%> (ø)
src/pytest_postgresql/janitor.py	63.82% <75.00%> (+0.19%)	⬆️
tests/conftest.py	100.00% <100.00%> (+13.04%)	⬆️
tests/test_noopexecutor.py	100.00% <100.00%> (ø)
src/pytest_postgresql/port.py	14.28% <0.00%> (-7.15%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cafaa30...6044532. Read the comment docs.