Add GitHub action to add items to official starters whenever supabase/examples update

[lyqht]

Description

At the moment, official starter items are manually retrieved from the supabase examples folder.

It will be nice if there's a GitHub action that will dynamically add an item whenever supabase adds a new example.

Acceptance Criteria

1. Please make sure that the action you're adding works — test it with act. Refer to this guide i wrote before on how to test github actions locally with act.
2. Please provide a repo that shows that the github action does work. — This repo (Repo A) need not update items based on the actual supabase folder; it can be from some other repo's folder (repo B) and you demonstrate that when you add items to that folder in Repo B, Repo A gets updated.