clean up cache

backend/build.gradle.kts

@@ -32,4 +32,10 @@ dependencies {
     compileOnly("org.lwjgl:lwjgl:${rootProject.properties["lwjgl_version"]}")
     // Fast util
     compileOnly("it.unimi.dsi:fastutil:${rootProject.properties["fastutil_version"]}")
-}
+}
+
+tasks.withType<JavaCompile> {
+    options.encoding = "UTF-8"
+    options.release.set(17)
+    dependsOn(tasks.clean)
+}