Fix Applications-Related Failure

A previous commit updates the definition of an application to include 'relationships'.
For  backwards compatibility this needs to be an optional field, which this commit fixes.

Author: twoseat

cloudfoundry-client/src/main/java/org/cloudfoundry/client/v3/applications/Application.java

@@ -17,6 +17,7 @@
 package org.cloudfoundry.client.v3.applications;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
+import org.cloudfoundry.Nullable;
 import org.cloudfoundry.client.v3.Lifecycle;
 import org.cloudfoundry.client.v3.Resource;
 import org.cloudfoundry.client.v3.spaces.SpaceRelationships;
@@ -42,6 +43,7 @@ public abstract class Application extends Resource {
      * The relationships
      */
     @JsonProperty("relationships")
+    @Nullable
     public abstract ApplicationRelationships getRelationships();
 
     /**