added gpg plugin in pom.xml to sign artifacts

Author: ktuukkan

pom.xml

@@ -189,6 +189,20 @@ 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>