Update to Kotlin version 1.4.0

Author: LukasLechnerDev

build.gradle

@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.3.71'
+    ext.kotlin_version = '1.4.0'
     repositories {
         google()
         jcenter()