Fix KotlinCore

KotlinCore/build.gradle.kts

@@ -18,19 +18,14 @@
  */
 
 plugins {
-    id("java")
+    steamwar.java
     kotlin("jvm") version "2.0.0"
-
-    id("com.github.johnrengelman.shadow")
+    alias(libs.plugins.shadow)
 }
 
 group = "de.steamwar"
 version = ""
 
-tasks.compileJava {
-    options.encoding = "UTF-8"
-}
-
 tasks.build {
     finalizedBy(tasks.shadowJar)
 }
@@ -44,22 +39,10 @@ java {
     targetCompatibility = JavaVersion.VERSION_21
 }
 
-sourceSets {
-    main {
-        java {
-            srcDirs("src/")
-        }
-        resources {
-            srcDirs("src/")
-            exclude("**/*.java", "**/*.kt")
-        }
-    }
-}
-
 dependencies {
     implementation(kotlin("reflect"))
 
-    compileOnly("io.papermc.paper:paper-api:1.21-R0.1-SNAPSHOT")
+    compileOnly(libs.paperapi21)
 }
 
 kotlin {