Use only standard well-known repositories and fix license header in build.gradle (#200)

diff --git a/build.gradle b/build.gradle
index 89ce0dd..9f0c0b5 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,9 +1,24 @@
+/**
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 buildscript {
   ext {
     springBootVersion = '2.0.2.RELEASE'
   }
   repositories {
     mavenCentral()
+    mavenLocal()
   }
   dependencies {
     classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
@@ -19,9 +34,8 @@
 }
 
 repositories {
-    maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }
-    jcenter()
     mavenCentral()
+    mavenLocal()
 }
 
 configurations {