build(gradle): Upgrade Gradle

6.8 -> 8.8

build.gradle

@@ -0,0 +1,22 @@
+wrapper {
+    gradleVersion = "8.8"
+    distributionType = Wrapper.DistributionType.BIN
+}
+
+subprojects { prj ->
+    apply plugin: "java"
+
+    group = "minecraft"
+    version = "1.8.8"
+
+    compileJava {
+        sourceCompatibility = targetCompatibility = JavaVersion.VERSION_1_8
+        options.encoding = "UTF-8"
+    }
+
+    repositories {
+        mavenLocal()
+        mavenCentral()
+        flatDir { dirs rootDir.toPath().resolve("libs").toFile() }
+    }
+}