Document beta vendordep (#936)

Author: calcmogul

docs/choreolib/installation.md

@@ -1,7 +1,11 @@
 Install ChoreoLib to your robot project by copy pasting the following link into the vendor library installation dialog:
 
 ```
+# Release
 https://sleipnirgroup.github.io/ChoreoLib/dep/ChoreoLib.json
+
+# Pre-season beta
+https://sleipnirgroup.github.io/ChoreoLib/dep/ChoreoLibBeta.json
 ```
 
 The installation method is the same as CTRE, PathPlanner, and more. Read more on Vendor Dependencies and their installation (VSCode —> install new library (online)) [here](https://docs.wpilib.org/en/stable/docs/software/vscode-overview/3rd-party-libraries.html#installing-libraries).