Beat Saber Mod Installer no longer updated

[Stevoisiak]

The README's installation instructions recommend using the Beat Saber Mod Installer. However, the mod installer was last updated on May 2019, 15 months ago. Unless the installer works with Beat Saber 1.11, it should be removed from the readme.

[brianhuang822]

Looks like this fork is working https://github.com/Top-Cat/CustomPlatforms

[brianhuang822]

Pulled multiple forks into a new fork. Tested against v1.11.0 of Beat Saber and cut a new release so that it will show up in ModAssistant.

https://github.com/brianhuang822/CustomPlatforms