Set up GitLab CI

@vasike - Yes, you are absolutely right. We definitely need to setup proper ci/cd with gitlab actions.

If you want, you can work on this and @lekso-surameli will review and we can merge it as soon as its done, so that we benefit from it.

+1 for this improvement. It is now clearly visible in pipelines https://git.drupalcode.org/project/gemini_provider/-/merge_requests/12/p... that there is work needed, at least for PHPCS and PHPStan, and of course the compatibility with next major version will be shown in the first job (composer build).

LGTM

@vasike thanks for the MR
@a.dmitriiev thanks for the review

Automatically closed - issue fixed for 2 weeks with no activity.