Hubifier
Simple Chrome extension to show github notifications as native notifications.
How to use
Download the extension from the releases page https://github.com/tenwiz/hubifier/releases
Drag the crx file to chrome and install it.
A new icon will appear next to your status bar and if you click it you will be prompted for a Private Access Token. You can get one following this instructions: https://help.github.com/en/articles/creating-a-personal-access-token-for-the-command-line#creating-a-token
You just need notification permissions.
And that's about it, this extension was created mostly for personal use so it might work or it might not.
Tested only on macOS.
Enjoy