example/ivy/android: update app version (1.4.0)

Add mavenCentral to repositories
needed to pull in necessary build tools dependencies

Change-Id: I9b8525430d4ba9535ad0d3bc6b4acd94f6ea0642
Reviewed-on: https://go-review.googlesource.com/c/mobile/+/360835
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Trust: Robert Findley <rfindley@google.com>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Hajime Hoshi <hajimehoshi@gmail.com>

Author: hyangah

example/ivy/android/app/build.gradle

@@ -6,8 +6,8 @@ android {
         applicationId 'org.golang.ivy'
         minSdkVersion 15
         targetSdkVersion 30
-        versionCode 3
-        versionName '1.0.2'
+        versionCode 4
+        versionName '1.4.0'
     }
     buildTypes {
         release {

example/ivy/android/build.gradle

@@ -12,6 +12,7 @@ buildscript {
 
 allprojects {
     repositories {
+        mavenCentral()
         google()
     }
 }