Bump Kotlin's version

Hubert Slojewski · Hubert Slojewski · commit a55587d60f86 · 2017-12-03T11:48:38.000+01:00
diff --git a/build.gradle b/build.gradle
@@ -2,7 +2,7 @@ group 'com.example.hoobie'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.1.4-3'
+    ext.kotlin_version = '1.2.0'
 
     repositories {
         mavenCentral()
