Update Java toolchain to version 25 in build script

Author: NonSwag

minestom/build.gradle.kts

@@ -1,3 +1,11 @@
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(25)
+}
+
+tasks.compileJava {
+    options.release.set(25)
+}
+
 dependencies {
     api(project(":core"))
     compileOnly("net.minestom:minestom:2025.10.31-1.21.10")