Add GitHub Actions

[eumiro]

Let's see whether this is a good replacement for the current .travis.yml file…

[codecov-io]

Codecov Report

Merging #128 (fa78071) into master (fba09fa) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #128   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         6           
  Lines          466       466           
=========================================
  Hits           466       466           

---

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 fba09fa...fa78071. Read the comment docs.

[eumiro]

Since the master branch does not contain GHA until now, we cannot see the results of the GHA CI run here.

[xflr6]

Thanks, left some comments.,

[eumiro]

BTW, the results of this PR can be found at https://github.com/eumiro/graphviz/actions

[eumiro]

Added a README.rst badge for the GHA CI. Please squash the commits afterwards.

[xflr6]

Sorry for the delay.

Still prefer not using tox in the CI and want to continue collecting coverage from all jobs (to cover for compat code branches).

Superseded by a0668ea and 78885a8, closing, thanks for the PR.