Excavator - Handle GitHub API rate limiting

Seems Excavator does not handle GitHub API rate limiting very well. Here is a run from Extras bucket: <https://github.com/ScoopInstaller/Extras/actions/runs/18555159620/job/52890740764> ```log Autoupdating appflowy The remote server returned an error: (403) rate limit exceeded. URL https://api.github.com/repos/AppFlowy-IO/AppFlowy/releases is not valid ```