Add support for generate_release_notes

[ncipollo]

Github now support automatically generating release notes, see: https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes.

This is also exposed in the create release call via generate_release_notes. Quick Link: https://docs.github.com/en/rest/reference/repos#create-a-release

---

Tasks

• Add action input associated with this field.
• Update the create call to use this input.
• Update tests.