doc: add HarshithaKP to collaborators

Fixes: https://github.com/nodejs/node/issues/34242

PR-URL: https://github.com/nodejs/node/pull/34417


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>