fix: do not revoke token if already expired

Closes #140

The pull request at #95 introduced changes to avoid revoking expired tokens by saving the expiresAt value in the state. The change, however, used core.setOutput instead of core.setState meaning the value is not saved in the state but rather available in the output.

if (!skipTokenRevoke) {
    core.saveState("token", authentication.token);
    core.setOutput("expiresAt", authentication.expiresAt);
  }

This means that when we use the value downstream, it evaluates to an empty string and the following code block is never run:

 const expiresAt = core.getState("expiresAt"); 
 if (expiresAt && tokenExpiresIn(expiresAt) < 0) { 
   core.info("Token expired, skipping token revocation"); 
   return; 
 }

This is a tiny PR to correct that typo.

actions / create-github-app-token

fix: do not revoke token if already expired #147