Cannot lint templates for an in-repo-addon

[KamiKillertO]

I would like to lint component's templates in an in-repo-addon, but they don't seem to be linted. I've try (in index.js)

isDevelopingAddon() {
  return true;
}

But it's not working 😢

[amk221]

Also affecting me

[buschtoens]

This might be a dupe of #292.