Upgrade to maven-assembly-plugin 2.5.5

Release notes:

http://mail-archives.apache.org/mod_mbox/maven-announce/201506.mbox/%3CCAJZRQKzc45axq2Vs0uVf2EZgR9hXEM-u7GbN4EZdd-ngEcZztw%40mail.gmail.com%3E

pom.xml

@@ -130,7 +130,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-assembly-plugin</artifactId>
-        <version>2.5.4</version>
+        <version>2.5.5</version>
         <configuration>
           <descriptors>
             <descriptor>src/main/assembly/jar-with-dependencies.xml</descriptor>