resolveStubDir method
Resolves the directory holding the make_plugin/ stub bundle. Tests
can override either this method directly or resolveArtisanRoot to
pin the bundle location.
@return Absolute path to the make_plugin stub bundle directory.
Implementation
@visibleForTesting
Future<String> resolveStubDir() async {
return p.join(await resolveArtisanRoot(), 'assets', 'stubs', 'make_plugin');
}