Provide a way to filter out unnecessary preparation

We could provide a way so that scheduled shipjs prepare won’t create unnecessary PRs with meaningless commits.

ref: https://github.com/algolia/shipjs/pull/644

[Haroenv]

That sounds like enough info for our use case at least

[eunjae-lee]

Since we have shouldRelease hook (which is not publicly documented, though), I guess shouldPrepare could make sense.

shouldPrepare({ commits, changelog, nextVersion, releaseType, releaseTag, commitNumbersPerType }) {
  /*
    commits: array of strings. `git log --pretty=format:%s` should be fine for this. (only titles)
    changelog: string. only the current version part.
    nextVersion: string.
    releaseType: 'major' | 'minor' | 'patch' | 'prerelease'
    releaseTag: 'latest' | 'alpha' | 'beta' | 'rc' | ... (whatever)
    commitNumbersPerType: { [type]: number } , for example, { 'feat': 10, 'chore': 3, fix: 4 } 
  */
}

In case of git diff, I can’t think of any example using it. It might be too difficult to handle programmatically…? We can add it any time.

What do you think?