add version checking, update discord URL, and add a message when you don't have perms

src/main/resources/plugin.yml

@@ -1,7 +1,7 @@
 name: TerminatorPlus
 main: net.nuggetmc.tplus.TerminatorPlus
 version: ${version}
-api-version: 1.16
+api-version: 1.16 # Set to 1.16 so the plugin loads, and we can tell the user that it may not be compatible with their version, because people can't scroll up.
 author: HorseNuggets
 
 permissions: