Update shadow plugin

Signed-off-by: Graham <gpe@openrs2.dev>

buildSrc/src/main/java/Versions.kt

@@ -22,6 +22,6 @@ object Versions {
     const val logback = "1.2.3"
     const val netty = "4.1.50.Final"
     const val openrs2Natives = "2.0.1"
-    const val shadowPlugin = "5.2.0"
+    const val shadowPlugin = "6.0.0"
     const val versionsPlugin = "0.28.0"
 }