add missing type of serviceTask in activiti-bpmn-extensions-5.15.xsd

Description

There is only one serviceTask - 'shell' in the xsd.
It will cause an error when edit .bpmn20.xml in eclipse xml editor.

Environment

None

Assignee

Tijs Rademakers

Reporter

Huisheng Xu

Labels

None

Components

Fix versions

Affects versions

Priority

Minor
Configure