example/ivy/android: upgrade gobind plugin to 0.2.6

For golang/go#15554

Also update app target sdk api to 23.

Change-Id: Id66b17b4388703e9806cc50def554b3c58606e24
Reviewed-on: https://go-review.googlesource.com/23690
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Elias Naur <elias.naur@gmail.com>

example/ivy/android/app/build.gradle

@@ -1,12 +1,12 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 22
-    buildToolsVersion "22.0.1"
+    compileSdkVersion 23
+    buildToolsVersion "23.0.3"
     defaultConfig {
         applicationId 'org.golang.ivy'
         minSdkVersion 15
-        targetSdkVersion 22
+        targetSdkVersion 23
         versionCode 3
         versionName '1.0.2'
     }
@@ -22,6 +22,6 @@ android {
 
 dependencies {
     compile fileTree(include: ['*.jar'], dir: 'libs')
-    compile 'com.android.support:appcompat-v7:22.1.1'
+    compile 'com.android.support:appcompat-v7:23.3.0'
     compile project(':ivy')
 }

example/ivy/android/ivy/build.gradle

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 plugins {
-    id "org.golang.mobile.bind" version "0.2.4"
+    id "org.golang.mobile.bind" version "0.2.6"
 }
 
 gobind {