[maven-release-plugin] prepare release v0.4.0

Author: haoyuan

pom.xml

@@ -19,7 +19,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>org.tachyonproject</groupId>
   <artifactId>tachyon</artifactId>
-  <version>0.4.0-SNAPSHOT</version>
+  <version>0.4.0</version>
   <packaging>jar</packaging>
   <name>Tachyon Project POM</name>
   <url>http://tachyonproject.org/</url>
@@ -34,7 +34,7 @@
     <connection>scm:git:git@github.com:amplab/tachyon.git</connection>
     <developerConnection>scm:git:git@github.com:amplab/tachyon.git</developerConnection>
     <url>scm:git:git@github.com:amplab/tachyon.git</url>
-    <tag>v0.3.0</tag>
+    <tag>v0.4.0</tag>
   </scm>
   <developers>
     <developer>