update gradle plugin & kotlin version

android/build.gradle

@@ -2,14 +2,14 @@ group 'net.touchcapture.qr.flutterqr'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.2.71'
+    ext.kotlin_version = '1.3.21'
     repositories {
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }