Add support for default merge commit params

[garrettheel]

Alternative to #1201, adds support for:

• squash_merge_commit_title
• squash_merge_commit_message
• merge_commit_title
• merge_commit_message

Note: there are currently some build errors with github.DependabotEncryptedSecret that depend on #1258. Will rebase after that is merged.

[gesellix]

@garrettheel #1258 has been merged.

[kfcampbell]

Once this PR is rebased, I can merge/release!

[garrettheel]

@kfcampbell I just rebased and bumped go-github up to v47

[kfcampbell]

Integration tests for these items are failing on main and failing here in the exact same way, so it's not a regression!

Thanks for doing this.

[scruplelesswizard]

@kfcampbell @garrettheel It looks like this change may not have considered repos that have merge and squash disabled (i.e. rebase only). It appears there is no way to not set these values, as "" is not a valid value, and nulling them applies the defaults.

I'm happy to throw up a PR, but first wanted to ask, is there a preferred way to patch this?

[kfcampbell]

@chaosaffe Hmm...I'm not sure! I don't know off the top of my head, sorry.

[garrettheel]

@chaosaffe would you mind creating a new issue to discuss? I'm curious what the negative impact there is in setting those defaults (is it just that a plan is generated?). I also don't know the answer off the top of my head, but happy to look into it with you

[danielpops]

Perhaps an answer to the above question(s), with the shipping of this PR, my terraform plans suddenly show this diff for every repo in my organization:

  # github_repository.repo["the_repo"] will be updated in-place
  ~ resource "github_repository" "repo" {
        id                          = "the_repo"
      + merge_commit_message        = "PR_TITLE"
      + merge_commit_title          = "MERGE_MESSAGE"
        name                        = "the_repo"
      + squash_merge_commit_message = "COMMIT_MESSAGES"
      + squash_merge_commit_title   = "COMMIT_OR_PR_TITLE"
        # (28 unchanged attributes hidden)
}

This does not seem useful or expected for me, and I imagine it may confuse others.

[garrettheel]

@danielpops @chaosaffe I created #1295 to track your concerns. Please use that to discuss.