Make sure the default tool bin dir or the user supplied is added to the PATH.
On Windows the tool dir and tool bin dir is moved to the TMP dir to take advantage of the fact that on GitHub hosted Windows runners this is on the faster D: drive
This PR adjusts the action so that it is no longer necessary to
explicitly specify the GitHub token to circumvent the API rate limit.
To this end, it simply passes the repository's GitHub token (available
via `${{ github.token }}`) as a default for the `github_token` action
input.
This is similar to how this is handled in, e.g.,
https://github.com/peter-evans/create-pull-request; specifically
[here](5354f85616/action.yml (L4-L6)).
