Update build.gradle.template

Updating project repository,
added jcenter() since Android Studio uses it by default.

https://www.jfrog.com/knowledge-base/why-should-i-use-jcenter-over-maven-central/
(cherry picked from commit 77c81a21d8)

platform/android/build.gradle.template

@@ -12,6 +12,7 @@ apply plugin: 'com.android.application'
 
 allprojects {
     repositories {
+    	jcenter()
 	mavenCentral()
 	$$GRADLE_REPOSITORY_URLS$$
     }