update gradle

Author: dongjunkun

build.gradle

@@ -5,8 +5,8 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.0.0-alpha3'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.3' // Add this line
+       classpath 'com.android.tools.build:gradle:2.2.0'
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.5' // Add this line
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files