Updated android maven plugin

The older plugin is incompatible with newer releases of gradle.
Newer gradle compatibility is required for DroidDriver to be built
as a subproject of projects that require a newer version of gradle.

com.github.dcendents:android-maven-plugin:1.2 is compatible with
gradle version n where 2.2 <= n < 2.4

com.github.dcendents:android-maven-gradle-plugin:1.3 is compatible
with gradle 2.4+

Change-Id: I42079dc0da92188b0258179fc7ca5ce0dc9a49fc
diff --git a/build.gradle b/build.gradle
index 207eaaf..3af6346 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,7 +2,7 @@
 // sdk.dir for the Android SDK path, you can run
 // $ ANDROID_HOME=/path/to/android-sdk gradle build
 
-// Gradle >= 2.1 required
+// Gradle >= 2.4 required
 buildscript {
     ext.bintrayUser    = project.hasProperty('bintrayUser') ? project.bintrayUser : System.getenv('BINTRAY_USER')
     ext.bintrayKey     = project.hasProperty('bintrayKey')  ? project.bintrayKey  : System.getenv('BINTRAY_KEY')
@@ -13,7 +13,7 @@
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:1.0.1'
-        classpath 'com.github.dcendents:android-maven-plugin:1.2'
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.3'
         classpath 'com.jakewharton.sdkmanager:gradle-plugin:0.12.0'
         if (bintrayEnabled) {
             classpath 'org.jfrog.buildinfo:build-info-extractor-gradle:3.0.3'