Migrate from TravisCI to GitHub Action

[shulard]

Since travis.org will be down soon, we need to migrate the CI pipeline to GitHub Action.

See: https://blog.travis-ci.com/oss-announcement

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[RCheesley]

Would you like me to set up Github Actions on the repo for you?

[shulard]

If you can I'll be happy to have some help here ^^

[RCheesley]

For sure - may be next week but will definitely take a look!

[RCheesley]

@shulard I have made a start on this in a draft WIP PR #112

I notice that WP actually already uses GitHub Actions here.

Maybe we can recycle / take inspiration from their workflows but I may need your assistance to understand what the tests will need and so forth - will ping you on Slack!

[shulard]

Hello @RCheesley !

Sorry for the late reply, I haven't got any time to work on this part... Their workflow is complicated and I don't know how GitHub action works already... I take a look and I think only their phpunit-tests.yml workflow is useful for us. All the others details are specific to WP releases...

At the beginning, I took inspiration from the official WP Travis configuration and I adapted it. Maybe it's a good start but I need to understand deeper their execution steps to be sure what to keep and what to remove...

[RCheesley]

Great - I haven't had time to come back to it since I started with the draft PR - hopefully we should be able to bring over some of the stuff they do.