Add Github CI action to build the project automatically

[hrj]

Adding this single file will automatically run a build via Github Actions.

Whenever a Pull Request is made, the action will check and inform if the build is failing.

(I think actions are enabled by default, but if they aren't, you can enable them in the Settings for this repository)

[hrj]

I have kept the workflow simple in this PR. It is also possible to run tests automatically, and to do this on multiple platforms. If you are interested, I can try to make a more elaborate action in a follow up PR.

[hrj]

Oh oops.. I just noticed you have Circle CI enabled on this repo! The PRs didn't have any checks on them, so I assumed that there is no CI.

Sorry for the spam!

(I do think Github Actions might be more convenient though since they are integrated into the Github UI)

[dstndstn]

Hi,
Thanks for this! Would you be willing to expand this to install all the dependencies and run the tests, eg as implemented in
https://github.com/dstndstn/astrometry.net/blob/master/.circleci/config.yml#L47
?

[hrj]

I tried expanding the tests. On Ubuntu 20.04, all goes well.

But Ubuntu 18.04 and CentOS are challenging, mainly because of python 3.x situation. Too many complex dependencies.

My many attempts (in a different branch):
https://github.com/UprootStaging/astrometry.net/actions