GitHub Actions

[corentincarton]

@doc78, I see that the GitHub actions are running for all the branches and all the commits, which is a bit overkill. Shouldn't we run them just for the PR to develop and master? Here's an example on how it could be done:
https://github.com/ecmwf/pyflow/blob/develop/.github/workflows/ci.yml

[doc78]

@corentincarton I actually use it to check the unit tests every time I push something new on any branch, instead of waiting for them to be merged in develop. However it is ok for me to limit the actions just on PR if it is annoying with many notifications.
Feel free to modify the ci.yml file and push it as you like.

[corentincarton]

@doc78 , thanks. I'll work on a PR with a new version of the ci that is activated only when we are ready to merge to develop. I think running it all the time on all the branches is a waste of resources and is indeed a bit annoying as we get ci failure notifications all the time.