put https://{base_url}/rest/user/avatar/update/
Updates a user avatar image uploaded as param in the post request.
The request must contain the id of the user to update an image to, as the avatar param. The provided image should have the 300*300 pixel size, otherwise, Kaleyra will automatically resize the image for you. The max size permitted to upload is 500 KB per file. The request will return the user avatar image URL.