`GITHUB_TOKEN` is not configured as an accepted input

[Nokel81]

Issue:

How To Reproduce:

1. Setup a github action that uses: butlerlogic/action-autotag@stable and specifies under with: the value GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}.
2. See that github outputs a warning about unexpected input.

Expected Behavior:

Github should not output a warning.

[panuhorsmalahti]

I believe env can be used instead.