We've a couple of dependencies which are used by both Minecraft and our core module. It's quite easy for these to get out-of-sync, causing confusing errors at runtime when the wrong version ends up on the classpath. We should have a task in the Minecraft-specific projects that checks the versions in our version catalogue match the versions required by Minecraft.

This includes:

• Guava
• FastUtil
• Netty
• slf4j

For our other dependencies, it might be nice to use something like gradle-versions-plugin or one of its related projects, to automate version updates.

We should probably also remove the cobalt-next dependency, and have some helper function to get the "next" version of a dependency.

Done in 78bb3da.