How do I run this action from different folder?

[jacklul]

My actions checkouts my main branch to $GITHUB_WORKSPACE but the folder I want the action to run on is in $GITHUB_WORKSPACE/gh-pages.
Using folder setting causes whole $GITHUB_WORKSPACE to be uploaded to gh-pages branch.
I want the action to upload $GITHUB_WORKSPACE/gh-pages contents to gh-pages branch.