Bump android gradle plugin to 3.2.0-rc03 and remove kotlin version from root gradle file

build.gradle

 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = '1.0.0'
     apply from: rootProject.file('dependencies.gradle')
 
     repositories {
@@ -11,7 +10,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.0-rc02'
+        classpath 'com.android.tools.build:gradle:3.2.0-rc03'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${versions.kotlin}"
         classpath "org.jetbrains.dokka:dokka-gradle-plugin:${versions.dokka}"
         classpath 'com.google.gms:google-services:4.0.2'