Make kotlin version a variable globally

app/build.gradle

@@ -104,7 +104,6 @@ dependencies {
     implementation "com.github.topjohnwu:room-runtime:${vRoom}"
     kapt "androidx.room:room-compiler:${vRoom}"
 
-    def kotlinVer = '1.3.50'
     implementation "org.jetbrains.kotlin:kotlin-stdlib:${kotlinVer}"
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${kotlinVer}"
 

build.gradle

@@ -7,6 +7,7 @@ if (configPath.exists())
     configPath.withInputStream { is -> props.load(is) }
 
 buildscript {
+    ext.kotlinVer = '1.3.50'
 
     repositories {
         google()
@@ -16,7 +17,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.0'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.50"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVer}"
 
 
         // NOTE: Do not place your application dependencies here; they belong