Added version numbers to maven plugins

The version numbers for several maven plugins were unspecified before, which
caused a bunch of warnings before.

Change-Id: I7e2e05ccf3e2f10b24010576eb78192e9d891120

simulation/JavaGazebo/pom.xml

@@ -6,7 +6,7 @@
   <artifactId>JavaGazebo</artifactId>
   <packaging>jar</packaging>
   <version>0.1.0-SNAPSHOT</version>
-  
+
   <profiles>
     <profile>
       <id>docline-java8-disable</id>
@@ -27,7 +27,7 @@
       </build>
     </profile>
   </profiles>
-  
+
   <dependencies>
     <dependency>
     	<groupId>com.google.protobuf</groupId>
@@ -56,6 +56,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-source-plugin</artifactId>
+		<version>2.3</version>
       </plugin>
     </plugins>
   </build>