support v2 notification_3rd, update version to 5.2.0.

Author: zhanq

README.md

@@ -15,13 +15,13 @@
 ## 1. 集成
 引入sdk包
 ```xml
-<!--以5.1.17版本为例-->
+<!--以5.2.0版本为例-->
 <dependencies>
         <!-- jiguang-sdk -->
         <dependency>
             <groupId>io.github.jpush</groupId>
             <artifactId>jiguang-sdk</artifactId>
-            <version>5.1.17</version>
+            <version>5.2.0</version>
         </dependency>
 </dependencies>
 ```

example-for-spring/pom.xml

@@ -13,7 +13,7 @@
 
     <groupId>io.github.jpush</groupId>
     <artifactId>example-for-spring</artifactId>
-    <version>5.1.17</version>
+    <version>5.2.0</version>
 
     <properties>
         <maven.compiler.source>8</maven.compiler.source>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>io.github.jpush</groupId>
             <artifactId>jiguang-sdk</artifactId>
-            <version>5.1.17</version>
+            <version>5.2.0</version>
         </dependency>
         <!-- lombok -->
         <dependency>

jiguang-sdk/pom.xml

@@ -7,12 +7,12 @@
     <parent>
         <groupId>io.github.jpush</groupId>
         <artifactId>jiguang-sdk-java</artifactId>
-        <version>5.1.17</version>
+        <version>5.2.0</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
     <artifactId>jiguang-sdk</artifactId>
-    <version>5.1.17</version>
+    <version>5.2.0</version>
     <packaging>jar</packaging>
 
     <properties>

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>io.github.jpush</groupId>
     <artifactId>jiguang-sdk-java</artifactId>
-    <version>5.1.17</version>
+    <version>5.2.0</version>
     <packaging>pom</packaging>
 
     <name>Jiguang SDK For Rest Api</name>