Update an existing viewmember in the specified view in the chosen project
 This is an HTTP PUT command.
 The Item can be serialized using JSON key value pairs,
 XML key value elements or Schema Objects (which serialize into XML or JSON).
 The keys must be user modifiable property names.
 The values are either primitive language types
 or integer ids of Micro Focus Hub higher level types (e.g. User, Label, View, etc).
 On successful update of the viewmember, it's entire post-commit property set is returned

 All viewmembers types are updatable, including items, traces and changepackages

  projectid the integer id of the chosen project
  viewid the integer id of a view of the project
  typeid the integer id of an item type from the server catalog
  sessionid a valid session for the logged on user running this query
  viewmember an XML or JSON representation of the viewmember to be updated and saved
 @return the created/updated view member

 usage example
 http://localhost:8080/MicroFocusHubRESTService/rest/viewmembers/projectid=0/viewid=1/typeid=2;sessionid=7c5ceef9-7c79-4b8f-83ba-cb6e082ddd1d