Add GPG sign plugin

Author: Arnaud Breton

pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.mailjet</groupId>
     <artifactId>mailjet-client</artifactId>
-    <version>4.1.0-SNAPSHOT</version>
+    <version>4.1.0</version>
     <packaging>jar</packaging>
     <name>Mailjet Client</name>
     <description>A Mailjet API Client</description>
@@ -126,6 +126,22 @@
                 <autoReleaseAfterClose>true</autoReleaseAfterClose>
               </configuration>
             </plugin>
+            <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-gpg-plugin</artifactId>
+              <executions>
+                <execution>
+                  <id>sign-artifacts</id>
+                  <phase>verify</phase>
+                  <goals>
+                    <goal>sign</goal>
+                  </goals>
+                </execution>
+              </executions>
+              <configuration>
+                <keyname>9BD3657DFD7A37FA</keyname>
+              </configuration>
+      </plugin>
         </plugins>
     </build>
 </project>