Add work item support to WebHookManager (#1215)

Author: ParkerMc

gitlab4j-api/src/main/java/org/gitlab4j/api/WebHookManager.java

@@ -23,6 +23,7 @@
 import org.gitlab4j.api.webhook.TagPushEvent;
 import org.gitlab4j.api.webhook.WebHookListener;
 import org.gitlab4j.api.webhook.WikiPageEvent;
+import org.gitlab4j.api.webhook.WorkItemEvent;
 
 /**
  * This class provides a handler for processing GitLab WebHook callouts.
@@ -186,6 +187,7 @@ public void handleEvent(Event event) throws GitLabApiException {
             case WikiPageEvent.OBJECT_KIND:
             case ReleaseEvent.OBJECT_KIND:
             case DeploymentEvent.OBJECT_KIND:
+            case WorkItemEvent.OBJECT_KIND:
                 fireEvent(event);
                 break;
 
@@ -270,6 +272,10 @@ public void fireEvent(Event event) throws GitLabApiException {
                 fireDeploymentEvent((DeploymentEvent) event);
                 break;
 
+            case WorkItemEvent.OBJECT_KIND:
+                fireWorkItemEvent((WorkItemEvent) event);
+                break;
+
             default:
                 String message = "Unsupported event object_kind, object_kind=" + event.getObjectKind();
                 LOGGER.warning(message);
@@ -337,6 +343,12 @@ protected void fireDeploymentEvent(DeploymentEvent deploymentEvent) {
         }
     }
 
+    protected void fireWorkItemEvent(WorkItemEvent workItemEvent) {
+        for (WebHookListener listener : webhookListeners) {
+            listener.onWorkItemEvent(workItemEvent);
+        }
+    }
+
     protected void fireReleaseEvent(ReleaseEvent releaseEvent) {
         for (WebHookListener listener : webhookListeners) {
             listener.onReleaseEvent(releaseEvent);

gitlab4j-models/src/main/java/org/gitlab4j/api/webhook/WebHookListener.java

@@ -76,6 +76,13 @@ default void onWikiPageEvent(WikiPageEvent wikiEvent) {}
      */
     default void onDeploymentEvent(DeploymentEvent deploymentEvent) {}
 
+    /**
+     * This method is called when a WebHook work item event has been received.
+     *
+     * @param workItemEvent the WorkItemEvent instance
+     */
+    default void onWorkItemEvent(WorkItemEvent workItemEvent) {}
+
     /**
      * This method is called when a WebHook release event has been received.
      *