Action cannot be used with GithHub app token

[rfratto]

Our project has recently switched to use a GitHub app token for all of our GitHub actions that cross multiple repositories. However, the /user endpoint does not work for GH app tokens:

action-homebrew-bump-formula/main.rb

Line 61 in df6d545

user = GitHub::API.open_rest "#{GitHub::API_URL}/user"

The action will always fail with:

/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/utils/github/api.rb:384:in `raise_error': GitHub API Error: Resource not accessible by integration (GitHub::API::AuthenticationFailedError)
HOMEBREW_GITHUB_API_TOKEN may be invalid or expired; check:
  https://github.com/settings/tokens

	from /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/utils/github/api.rb:285:in `open_rest'
	from /home/runner/work/_actions/dawidd6/action-homebrew-bump-formula/v3/main.rb:61:in `<module:Homebrew>'
	from /home/runner/work/_actions/dawidd6/action-homebrew-bump-formula/v3/main.rb:17:in `<main>'