Move CI to GitHub actions

[aurelien-reeves]

Description

Moving the CI from Circle CI to Gihub actions.

Regular (ubuntu) builds: ✔
Windows builds: ✔
JRuby build: ✔
🆕 MacOS builds 🆕: ✔

The previous GitHub workflow was designed to push to cucumber reports, but it did not worked anymore since personal tokens have been deprecated on reports. It has been removed, we may consider recreating a dedicated workflow for that purpose if we want to, with a new collection token.

If we want to activate back the CCK tests, we could created a dedicated workflow too

I noticed that we are using a pretty old version of Rubocop, and updating it reveals a lot of offenses. I suggest to try upgrading it as part of another PR to avoid blocking this one.

Type of change

Please delete options that are not relevant.

• Refactoring (improvements to code design or tooling that don't change behaviour)

Checklist:

Your PR is ready for review once the following checklist is
complete. You can also add some checks if you want to.

• New and existing tests are passing locally and on CI
• bundle exec rubocop reports no offenses

[aurelien-reeves]

It seems that the build does not work on windows with ruby 2.5 for unknown reason.
Still, we have ruby 2.6, 2.7 and 3.0 which are running on Windows successfully. With circle-ci, we had only one build, and I can't even figure out which version of ruby it is.

[olleolleolle]

I am for going forward with this as it is now.

[luke-hill]

Should probably optimise this method whilst we're here.