WIP: Migrate Travis jobs to GitHub Actions

[GuillaumeFavelier]

This PR follows #8335 (comment) and migrates all remaining jobs on Travis to GitHub Actions.

ToDo:

• Migrate Travis jobs
• Remove travis conf file
• Try separate jobs to fix compat / old job
• Add inline annotations for codespell and flake (suggested in MRG: Plot label time course with Brain #8335 (comment))
• Remove TRAVIS_OS_NAME variable
• Add [skip azp] mechanism (suggested in WIP: Migrate Travis jobs to GitHub Actions #8514 (comment))

This is still work in progress.

[larsoner]

While you're digging around in CIs, could you add a step to all Azure runs that actually checks the commit message for [skip azp], [azp skip], and [ci skip] and just exit the run with succeeded status if detected? I've been hoping for months that Azure would add native support for this but they haven't.

I see two ways of doing it:

1. Reuse a bit of code in each job, which you could adapt from SciPy here:

   https://github.com/scipy/scipy/blob/master/.circleci/config.yml#L11

2. Make a "check skip" job that all other jobs depend on, and only run the other jobs if the check skip job says to do so. I don't think this will bottleneck things much since this job would run very quickly, then all N other Azure jobs would spawn.

Not sure which is better, or if there is another better alternative

[GuillaumeFavelier]

Finally a skip. Now I have to work on a reliable conditional

[GuillaumeFavelier]

Okay I think Azure is good to go now

[larsoner]

Separate files would be better for restartability

[GuillaumeFavelier]

I'll separate them all then

[larsoner]

Yes the GitHub ones (Azure can and should stay a single file)

[larsoner]

same

[larsoner]

Maybe codespell_and_flake ?

[larsoner]

Suggested change

	- bash: |
	make flake
	displayName: make flake
	condition: always()

[larsoner]

Suggested change

	- bash: |
	make codespell-error
	displayName: make codespell-error
	condition: always()

[GuillaumeFavelier]

For future reference, I got the infos of the correct usage of stage& dependencies from:

microsoft/azure-pipelines-tasks#4743 (comment)

[GuillaumeFavelier]

This is ready for reviews but:

1. I still have doubts about compat / old job (it failed in baae1d1 for example). The failure seems random and I don't notice any big differences compared to the Travis environment.

2. The GitHub actions don't react to [skip ci], [ci skip] ...etc. And this could be fixed in another PR

[larsoner]

@GuillaumeFavelier our minimum is 1.15 and that part of the test is skipped for 1.16+, we should just skip it entirely. For now maybe just comment it out so that someday we come back to it?

[larsoner]

I'll merge and we can iterate more as necessary, thanks @GuillaumeFavelier !

[agramfort]

can you update the badges on readme @GuillaumeFavelier ? thanks heaps !

[larsoner]

Looks like you can make them for GitHub actions like https://github.com/mne-tools/mne-python/workflows/linux%20/%20conda/badge.svg?branch=master:

[cbrnr]

Great work! Do we have any numbers on how long tests take on GitHub Actions vs. how long they took on Travis? AFAIK the longest job on Travis was around 50-55 minutes...

[larsoner]

Yes the pip pre linux on Travis was 50-55, looks like on the last green check mark above this job was ~40 minutes