build: use GITHUB_ENV file to set env variables

The other way is deprecated.

PR-URL: https://github.com/nodejs/node/pull/35638


Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>