Update build scripts: migrate to Spigot API, adjust JVM toolchains and Java version.

Signed-off-by: Chaoscaot <max@maxsp.de>

KotlinCore/build.gradle.kts

@@ -31,8 +31,7 @@ tasks.shadowJar {
 }
 
 dependencies {
-    compileOnly(libs.paperapi21)
-    compileOnly(libs.nms21)
+    compileOnly(libs.spigotapi)
     compileOnly(project(":SpigotCore"))
 
     implementation(libs.exposedCore)

TNTLeague/build.gradle.kts

@@ -21,6 +21,15 @@ plugins {
     steamwar.kotlin
 }
 
+kotlin {
+    jvmToolchain(21)
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+}
+
 dependencies {
     compileOnly(libs.paperapi21)
     compileOnly(project(":SpigotCore", "default"))

buildSrc/src/steamwar.kotlin.gradle

@@ -23,12 +23,12 @@ plugins {
 }
 
 kotlin {
-    jvmToolchain(21)
+    jvmToolchain(8)
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_21
-    targetCompatibility = JavaVersion.VERSION_21
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
 }
 
 tasks.compileJava {