GitLab

* Adds Mask2Former to transformers
Co-authored-by: Shivalika Singh <shivalikasingh95@gmail.com>
Co-authored-by: Shivalika Singh <73357305+shivalikasingh95@users.noreply.github.com>
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>