Merge master @ d59a46cd to work/73847-tagged-uml :

umbrello/uml1model/umlobject.h
- Non virtual function save1end saves possible stereotype tagged values
  of m_TaggedValues and writes the XML end element created in save1().

umbrello/uml1model/umlobject.cpp
- Move saving of m_TaggedValues from UMLObject::save1 to save1end.
  Reason: A nested XML element is created by the writing of
  m_TaggedValues. Callers of save1 often write additional attributes
  after the call. However, additional attributes may not follow
  elements.

umbrello/uml1model/actor.cpp
umbrello/uml1model/artifact.cpp
umbrello/uml1model/attribute.cpp
umbrello/uml1model/category.cpp
umbrello/uml1model/checkconstraint.cpp
umbrello/uml1model/classifier.cpp
umbrello/uml1model/component.cpp
umbrello/uml1model/datatype.cpp
umbrello/uml1model/entityattribute.cpp
umbrello/uml1model/entity.cpp
umbrello/uml1model/enum.cpp
umbrello/uml1model/enumliteral.cpp
umbrello/uml1model/foreignkeyconstraint.cpp
umbrello/uml1model/instanceattribute.cpp
umbrello/uml1model/instance.cpp
umbrello/uml1model/node.cpp
umbrello/uml1model/operation.cpp
umbrello/uml1model/package.cpp
umbrello/uml1model/port.cpp
umbrello/uml1model/usecase.cpp
- In function saveToXMI1 replace final call to writer.writeEndElement()
  by call to UMLObject::save1end(writer).

umbrello/version.h
- Set XMI_FILE_VERSION to "1.6.21".