change dubbo version to 2.5.7
diff --git a/pom.xml b/pom.xml
index 481a537..0f711e6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,7 +50,7 @@
 		<dependency>
 			<groupId>com.alibaba</groupId>
 			<artifactId>dubbo</artifactId>
-			<version>2.5.7-SNAPSHOT</version>
+			<version>2.5.7</version>
 		</dependency>
 		<dependency>
 			<groupId>io.netty</groupId>