meta: add startup team in CODEOWNERS

PR-URL: https://github.com/nodejs/node/pull/35406
Fixes: https://github.com/nodejs/node/issues/35215


Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>