We were using one token for both pushing to the llvmbot fork and for
creating a pull request against the www-releases repository, since the
fork and the repository have different owners, we were using a classic
access token which has very coarse-grained permissions. By using two
separate tokens, we limit the permissions to just what we need to do the
task.
This is a re-commit of b6ee085068 minus
the environment changes which were causing the workflow to fail.
48dffbc654