feat: Migrate tests to use new api-commons testing package

Fixes #13 (closed)

src/main/java/org/eclipsefoundation/wg/resource/WorkingGroupsResource.java

@@ -12,6 +12,7 @@
  */
 package org.eclipsefoundation.wg.resource;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
@@ -44,7 +45,7 @@ public class WorkingGroupsResource {
     @GET
     public Response getWorkingGroups(@QueryParam("status") List<String> statuses) {
         // return the results as a response
-        return Response.ok(wgService.get(statuses)).build();
+        return Response.ok(new ArrayList<>(wgService.get(statuses))).build();
     }
 
     @GET