WELD-2771 Housekeeping in Groovy SE example

Author: manovotn

examples/se/groovy-numberguess/pom.xml

@@ -57,7 +57,6 @@
             <plugin>
                 <groupId>org.codehaus.gmavenplus</groupId>
                 <artifactId>gmavenplus-plugin</artifactId>
-                <version>1.13.1</version>
                 <executions>
                     <execution>
                         <goals>