Fixes #5237 by defining the correct type for group.pod.

Test Plan: read documentation

Reviewers: jdef, meichstedt, jenkins, unterstein

Reviewed By: jdef, meichstedt, jenkins, unterstein

Subscribers: marathon-team

Differential Revision: https://phabricator.mesosphere.com/D535

docs/docs/rest-api/public/api/v2/types/group.raml

@@ -1,7 +1,7 @@
 #%RAML 1.0 Library
 uses:
   app: app.raml
-  pod: podStatus.raml
+  pod: pod.raml
   strings: stringTypes.raml
   pragma: pragma.raml
 types:
@@ -15,7 +15,7 @@ types:
         uniqueItems: true
       pods?:
         type: array
-        items: pod.PodStatus
+        items: pod.Pod
         uniqueItems: true
       groups?:
         type: array