Merge pull request #75 from xiaowing/release

update the version of sdk to 0.3.1

Author: xiaowing

README.md

@@ -21,7 +21,7 @@ The recommended way to use the Aliyun TSDB SDK for Java in your project is to co
 <dependency>
     <groupId>com.aliyun</groupId>
     <artifactId>hitsdb-client</artifactId>
-    <version>0.2.6</version>
+    <version>0.3.1</version>
 </dependency>
 ```
 

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>com.aliyun</groupId>
 	<artifactId>hitsdb-client</artifactId>
-	<version>0.3.0</version>
+	<version>0.3.1</version>
 	<name>Aliyun TSDB SDK for Java</name>
 	<description>The Alibaba TSDB SDK for Java used for accessing High Performance Time Series Database</description>
 	<url>https://www.aliyun.com/product/hitsdb</url>