Add support for importing organization-level webhooks

[mhuxtable]

This introduces support for importing webhooks from GitHub organization
objects. This was already supported for repository-level webhooks, and
the implementation is similar with the exception of some changes to ID
handling.

[MPV]

I created #493 and was happy to discover this PR just now.

@mhuxtable Looks like there's a conflict in github/resource_github_organization_webhook_test.go — would you like to take a look? 😊

[mhuxtable]

I created #493 and was happy to discover this PR just now.

@mhuxtable Looks like there's a conflict in github/resource_github_organization_webhook_test.go — would you like to take a look? 😊

@MPV That's done, and your comment prompted me to complete an outstanding TODO by updating the docs – thanks.

If you wanted to use this locally before it's merged, you should be able to build it and use it provided it's on your path. I give my locally built providers a unique version suffix e.g. 2.8.1-org, which I specify in the version property of the provider to ensure the expected instance is used.

I've used this just recently to import org webhooks to an existing GitHub organization. I hope you can make use of it too!

[MPV]

Seems this PR isn't mergable now due to it now has conflicts?

[jcudit]

🤔 not sure why the acceptance tests are having such a hard time. It may have something to do with the age of this PR 😊 .

I've copied the commits into another branch and have observed tests pass for individual accounts. Happy to merge despite the failing checks and can follow up with corrections to organization account testing in a separate PR. Thanks to all who've waited / contributed 🙇 .