Only use github.token on github.com (#443)

* Only use github.token on github.com

This expression evaluates to `''` if called from GHES hosted elsewhere
You can still provide your token on both github.com and GHES

* Enshure blank result of expression and not false

* Revert "Revert "Pass the `token` input through on GHES (#427)" (#437)"

This reverts commit cf86e08a31433e1dc61981fa0301f2adc9606f46.

* fix typo

* Add back the doc on the tool cache for self-hosted

Co-authored-by: Brian Cristante <33549821+brcrista@users.noreply.github.com>