Add production-ready GitLab CI template

[miskeens]

Proposal

Add GitLab CI template so GitLab users could simply include the template to lint their code.

[hound672]

Could you make PR?)

[miskeens]

Sure, right after #51 is resolved

[Yakwilik]

I think, it is already resolved, we have docker image, could you make a PR?

[Yakwilik]

you can use:

docker pull ghcr.io/easyp-tech/easyp:v0.11.3

[Yakwilik]

@miskeens I think, it is already resolved, we have docker image, could you make a PR?