[Feature] Support resolving lockfile merge conflicts from git revert

[merceyz]

• I'd be willing to implement this feature (contributing guide)
• This feature is important to have in this repository; a contrib plugin wouldn't do

Describe the user story

Yarn currently supports resolving merge conflicts in the lockfile caused by git merge, git rebase, and git cherry-pick but not git revert.

Describe the solution you'd like

Support resolving merge conflicts from git revert by checking git rev-parse REVERT_HEAD HEAD here:

berry/packages/plugin-essentials/sources/commands/install.ts

Lines 392 to 406 in 580f593

	let commits = await execUtils.execvp(`git`, [`rev-parse`, `MERGE_HEAD`, `HEAD`], {
	cwd: configuration.projectCwd,
	});
	if (commits.code !== 0) {
	commits = await execUtils.execvp(`git`, [`rev-parse`, `REBASE_HEAD`, `HEAD`], {
	cwd: configuration.projectCwd,
	});
	}
	if (commits.code !== 0) {
	commits = await execUtils.execvp(`git`, [`rev-parse`, `CHERRY_PICK_HEAD`, `HEAD`], {
	cwd: configuration.projectCwd,
	});
	}