Add Project-level MR approvals

[husunal]

This MR adds a Project-level MR approvals resource.

[husunal]

Any idea why TestAccGitlabServiceJira_basic started to fail?

##[error] TestAccGitlabServiceJira_basic: testing.go:684: Step 1 error: Check failed: Check 2/8 error: gitlab_service_jira.jira: Attribute 'url' expected "https://testurl.com", got "https://test.com"?
https://github.com/terraform-providers/terraform-provider-gitlab/pull/356/checks?check_run_id=834966420#step:5:168

[armsnyder]

Looks great! A few comments.

[husunal]

Can we run acceptance-ee tests on pull_requests? When we use isRunningInCE in SkipFunc we don't run ee only tests in actions.

[horjulf]

Shouldn't this be part of the gitlab_project resource ?
There are already some MR check options in that resource (e.g. approvals_before_merge), this seems to be unique per project, so would make sense to keep it all in one place.

[husunal]

@horjulf totally makes sense but the API doesn't support it https://docs.gitlab.com/ee/api/projects.html#create-project

[horjulf]

@horjulf totally makes sense but the API doesn't support it https://docs.gitlab.com/ee/api/projects.html#create-project

I see, that does make it tricky to manage in a single resource 🤔

[jeremad]

Do you need any help with this one? I'd really like to see this released. I can have a look at your failing test!

[husunal]

@jeremad feel free to contribute. I’ ve tested the module and the tests on a Gitlab EE but it fails in Github actions despite the SkipFunc which should be skipping tests for community edition and run for EE only.

[jeremad]

I think it is expected that the tests run but they should be skipped immediately and only take a few ms (at least that's what happens with GitHub tests on master: https://github.com/terraform-providers/terraform-provider-gitlab/runs/936184044?check_suite_focus=true)

[armsnyder]

You also need to add your new doc page to website/gitlab.erb.

[jeremad]

I fixed the review comments, squashed the commits and rebased on master I can open another MR, or you can push force that here:
https://github.com/jeremad/terraform-provider-gitlab/tree/feature/gitlab_project_approval_configuration

[armsnyder]

LGTM. The only remaining thing would be changing project_id type to TypeInt, but that's minor.

[husunal]

Do we need additional approvals before merge?

Adding @nicholasklick

[armsnyder]

Looks like this needs rebasing @husunal

[husunal]

Thanks, rebased @nicholasklick @armsnyder

[armsnyder]

Thanks! This looks ready to merge @nicholasklick