Remove shadow from build classpath

it isn't used

build.gradle.kts

@@ -11,7 +11,6 @@ import kotlin.io.path.*
 plugins {
     java
     `maven-publish`
-    id("com.github.johnrengelman.shadow") version "8.1.1" apply false
     id("io.papermc.paperweight.core") version "1.6.0"
 }