resolves #800: Add WaitForState support for resource_gitlab_project branch protection

[RicePatrick]

This fixes an issue where branch protection ran in the background when creating a project, causing the default branch to occasionally not be protected.

Description

Closes #800
There was a race condition apparent in project creation where occasionally the branch protection would return false even though the branch had been protected asynchronously. This could cause issues if downstream resources used that output value. This also caused several tests that checked the branch protection status to be flakey and seemingly appear to fail rendomly when they were, in fact, failing properly.

PR Checklist

• Resource attributes match 1:1 the names and structure of the API resource in the GitLab API documentation.
• Examples are updated with:
  • A *.tf file for the resource/s with at least one usage example
  • A *.sh file for the resource/s with an import example (if applicable)
• New resources have at minimum a basic test with three steps:
  • Create the resource
  • Update the attributes
  • Import the resource
• No new //lintignore comments that came from copied code. Linter rules are meant to be enforced on new code.

[RicePatrick]

OK, well this is embarrassing given I'd run those tests locally. Investigating.

[RicePatrick]

OK, note to self. Don't forget when running make testacc locally to remove the limiter you put on it to only run your specific tests. Whoops.

The issue here was that if you don't set default_branch or initialize_with_readme, then the default branch obviously throws a 404 when you attempt to query it. Similar to other situations where this happens, I now catch the 404 status and exit the WaitForState loop.

I'm oddly still getting one failing test with this change, related to a data source for an archived project not returning an empty state. I wouldn't have changed that behavior I'd think, but I'm going to go ahead and commit the changes for tonight and keep looking at it tomorrow.

Hey Adam, I'm trying to "dismiss your review" in hope that I'm able to merge :D Thanks 🍻

[timofurrer]

@PatrickRice-KSC thanks for the deep-dive into what caused this and thanks for the fix! Much appreciated 🎉

[github-actions]

This functionality has been released in v3.10.0 of the Terraform GitLab Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue. Thank you!