Skip signing graal-native-test module. (#2675)

Author: eamonnmcmanus

graal-native-image-test/pom.xml

@@ -104,6 +104,14 @@
             <skip>true</skip>
           </configuration>
         </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-gpg-plugin</artifactId>
+          <configuration>
+            <!-- Not deployed -->
+            <skip>true</skip>
+          </configuration>
+        </plugin>
       </plugins>
     </pluginManagement>