Inline versions to fix Renovate (#110)

build.gradle

@@ -2,16 +2,12 @@ import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
 
 buildscript {
-  ext.versions = [
-    'kotlin': '1.9.0',
-    'serialization': '1.5.1',
-  ]
   repositories {
     mavenCentral()
   }
   dependencies {
-    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${versions.kotlin}"
-    classpath "org.jetbrains.kotlin:kotlin-serialization:${versions.kotlin}"
+    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.0"
+    classpath "org.jetbrains.kotlin:kotlin-serialization:1.9.0"
     classpath 'com.diffplug.spotless:spotless-plugin-gradle:6.25.0'
     classpath 'com.vanniktech:gradle-maven-publish-plugin:0.27.0'
   }
@@ -31,13 +27,13 @@ repositories {
 
 dependencies {
   api "com.squareup.retrofit2:retrofit:2.9.0"
-  api "org.jetbrains.kotlinx:kotlinx-serialization-core:${versions.serialization}"
+  api "org.jetbrains.kotlinx:kotlinx-serialization-core:1.5.1"
 
   testImplementation "junit:junit:4.13.2"
   testImplementation "com.squareup.okhttp3:mockwebserver:4.12.0"
   testImplementation "com.google.truth:truth:1.4.2"
-  testImplementation "org.jetbrains.kotlinx:kotlinx-serialization-protobuf:${versions.serialization}"
-  testImplementation "org.jetbrains.kotlinx:kotlinx-serialization-json:${versions.serialization}"
+  testImplementation "org.jetbrains.kotlinx:kotlinx-serialization-protobuf:1.5.1"
+  testImplementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.5.1"
 }
 
 tasks.withType(KotlinJvmCompile).configureEach { task ->