[Chapel Merge] Migrate our sphinx domain to github actions

Branch: refs/heads/master
Revision: 7be5c5b
Author: ronawho
Link: Migrate to github actions by ronawho · Pull Request #52 · chapel-lang/sphinxcontrib-chapeldomain · GitHub
Log Message:

Merge pull request #52 from ronawho/github-actions

Migrate our sphinx domain to github actions

[reviewed by @lydia-duncan]

Migrate from Travis to Github Actions. Travis is no longer free (or well
supported), so migrate to github actions. For the most part this is a
direct transliteration of the Travis job, but the main coveralls
github-action doesn't work with xml (coverallsapp/github-action#30), so
switch to using codecov, which provides similar functionality.

Here's some resources I used:

Resolves Cray/chapel-private#1804

Modified Files:
A .github/workflows/CI.yml

R .travis.yml
M docs/developers.rst
M test-requirements.txt

Compare: https://github.com/chapel-lang/sphinxcontrib-chapeldomain/compare/f804ba41b9ef...7be5c5bedc8c