Use spotless in buildSrc

Author: daymxn

buildSrc/build.gradle.kts

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 plugins {
-    id("com.ncorti.ktfmt.gradle") version "0.20.1"
     alias(libs.plugins.kotlinx.serialization)
+    alias(libs.plugins.spotless)
     `kotlin-dsl`
 }
 
@@ -26,15 +26,23 @@ repositories {
     maven(url = "https://plugins.gradle.org/m2/")
 }
 
+spotless {
+    java {
+        target("src/**/*.java")
+        targetExclude("**/test/resources/**")
+        googleJavaFormat("1.22.0").reorderImports(false).skipJavadocFormatting()
+    }
+    kotlin {
+        target("src/**/*.kt")
+        ktfmt("0.52").googleStyle()
+    }
+}
+
 // Refer latest "perf-plugin" released version on https://maven.google.com/web/index.html?q=perf-plugin#com.google.firebase:perf-plugin
 // The System property allows us to integrate with an unreleased version from https://bityl.co/3oYt.
 // Refer go/fireperf-plugin-test-on-head for more details.
 val perfPluginVersion = System.getenv("FIREBASE_PERF_PLUGIN_VERSION") ?: "1.4.1"
 
-ktfmt {
-    googleStyle()
-}
-
 dependencies {
     // Firebase performance plugin, it should be added here because of how gradle dependency
     // resolution works, otherwise it breaks Fireperf Test Apps.