build.gradle: search for artifacts at MavenCentral before trying JCenter

build.gradle

@@ -3,6 +3,7 @@ import java.nio.file.StandardCopyOption;
 
 buildscript {
     repositories {
+        mavenCentral()
         google()
         jcenter()
         maven {
@@ -19,6 +20,7 @@ buildscript {
 
 allprojects {
     repositories {
+        mavenCentral()
         google()
         jcenter()
     }