Release the generator to include fixes for Librarian

[pearigee]

We have made several modifications to the generator as a part of the librarian migration. We need to release these in order to prevent regeneration.

Changes we need to release (as of Friday):

• google-cloud-node: remove per-library .gitattributes or move to repo root librarian#4582
• google-cloud-node: remove CODE_OF_CONDUCT.md, CONTRIBUTING.md, and LICENSE from per-library directories librarian#4273