Revert "added gpg plugin in pom.xml to sign artifacts"

This reverts commit d2346ca.

Author: ktuukkan

pom.xml

@@ -189,20 +189,6 @@ along with Java Marine API. If not, see <http://www.gnu.org/licenses />.
                     <target>1.8</target>
                 </configuration>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-gpg-plugin</artifactId>
-                <version>1.5</version>
-                <executions>
-                    <execution>
-                    <id>sign-artifacts</id>
-                    <phase>verify</phase>
-                    <goals>
-                        <goal>sign</goal>
-                    </goals>
-                    </execution>
-                </executions>
-                </plugin>
         </plugins>
     </build>