When creating a github pull request change object, the statuses of the
head commit are fetched, and the latest status of each user and context
set is appended into a list of statuses. The string is
'user:context:state', where state can be success, error, or failure.
Context is freeform, and the user is the login of the entity that set
the status.
Tests have been added to validate that github based requirements on
pipelines are honored.
Change-Id: I45abbd6cbddd36b8491bdf9bb8d545216537ad2f
Signed-off-by: Jesse Keating <omgjlk@us.ibm.com>
d96e5887b8