Switch CI to Github Actions

[clementval]

The free Travis CI for OSS will end on June 15th. I have put together a simple Github Action to re-create the same workflow for CI. It is still not fully complete but it does the job.

I propose to disable Travis and rely on Github Actions from now on. @lxavier are you ok with this?

Hi! It seems there are still plenty of builds running. We're pushing back the shutdown date to June 15th.
Please consider migrating to travis-ci.com.

[lxavier]

yes please go ahead

[lxavier]

Although 15 is apssed and seems we still have travis working

[clementval]

It sends the request but it does not execute the script. The GitHub actions is the only that report a result

[lxavier]

ok

[clementval]

I disabled it but I think it stays for the PR that triggered it when it was enable.