解决AndroidStudio编译时报错：Could not resolve all artifacts for configuration ':classpath'；

升级完AndroidStudio3.6.1编译项目报错：

Caused by: org.gradle.api.internal.artifacts.ivyservice.DefaultLenientConfiguration$ArtifactResolveException: Could not resolve all artifacts for configuration ‘:classpath’.

提示错误：Read Time out

即使开了梯子依然下载超时，我们更换为阿里云的maven库，下载速度会更快一点。

将原来配置：

buildscript {
	repositories {
	        google()
	        jcenter()  
	    }
    }
allprojects {
	repositories {
	        google()      
	        jcenter()
	        }
    }

改为：

buildscript {
	repositories {
	        google()
	        maven{url 'http://maven.aliyun.com/nexus/content/groups/public/'}
	        jcenter()
	       } 
    }
allprojects {
	repositories {
	        google()
	        maven{url 'http://maven.aliyun.com/nexus/content/groups/public/'}
	        jcenter()
	        }
    }

等待一小会Gradle sync成功