Remove an unnecessary plugin definition

Signed-off-by: Mark Thomas <markt@apache.org>
diff --git a/api/pom.xml b/api/pom.xml
index ba41861..8bc141a 100644
--- a/api/pom.xml
+++ b/api/pom.xml
@@ -282,12 +282,6 @@
                     <findbugsXmlWithMessages>true</findbugsXmlWithMessages>
                 </configuration>
             </plugin>
-            
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-gpg-plugin</artifactId>
-                <version>1.6</version>          
-            </plugin>
         </plugins>
     </build>