tools: make GH Actions workflows work if default branch is not master

PR-URL: https://github.com/nodejs/node/pull/38516


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Mary Marchini <oss@mmarchini.me>