Mention Needed Permissions

[kferrone]

Somewhere in the docs/readme should mention what permissions are needed. I can figure it out but I would like to be dumb and read a very obvious statement that says you must have permissions to pull requests for the token you use.

[intentionally-left-nil]

You could mention the permissions for the rest of us :D

The ones I've used are:

permissions:
  contents: read
  pull-requests: write