Migrate CI to GitHub Actions

[duncanmmacleod]

This PR updates the CI to use GitHub Actions

[codecov]

Codecov Report

Merging #332 (de82675) into master (9136ade) will decrease coverage by 0.16%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #332      +/-   ##
==========================================
- Coverage   50.47%   50.31%   -0.16%     
==========================================
  Files          60       60              
  Lines        8636     8658      +22     
==========================================
- Hits         4359     4356       -3     
- Misses       4277     4302      +25     

Flag	Coverage Δ
Linux	50.31% <0.00%> (-0.16%)	⬇️
macOS	50.31% <0.00%> (?)
python3.10	50.31% <0.00%> (?)
python3.7	49.51% <0.00%> (?)
python3.8	50.31% <0.00%> (?)
python3.9	50.31% <0.00%> (?)
python36	?
python37	?
python38	?
python39	?

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

Impacted Files	Coverage Δ
gwsumm/tabs/fscan.py	14.57% <0.00%> (-2.48%)	⬇️
gwsumm/plot/guardian/__main__.py	98.82% <0.00%> (-1.18%)	⬇️
gwsumm/plot/triggers/__main__.py	98.10% <0.00%> (-0.95%)	⬇️
gwsumm/batch.py	99.58% <0.00%> (-0.42%)	⬇️

---

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 5368f1d...de82675. Read the comment docs.

[eagoetz]

LGTM