增加一些镜像

墙太厉害了！
'io.fabric.tools:gradle:1.31.2'
'de.timfreiheit.resourceplaceholders:placeholders:0.3'
这俩一直报错

build.gradle

@@ -6,6 +6,8 @@ buildscript {
         google()
         //jcenter()
         maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
+        maven { url 'http://s3.amazonaws.com/fabric-artifacts/public' }
+        maven { url 'https://maven.aliyun.com/repository/gradle-plugin' }
         maven { url 'https://maven.fabric.io/public' }
         maven { url 'https://plugins.gradle.org/m2/' }
     }