Allow editing of notes via the api
Created by: kolbyjack
Adds the ability to edit notes using a POST to the existing GET endpoint for fetching an individual note. The user editing the note must be the same one who created it.
Tested using curl:
curl -H "PRIVATE-TOKEN: " -H "Content-Type: application/json" https://gitlab/api/v3/projects/51/merge_requests/11/notes/38 -d '{"body": "