fix readme example for creating workitem

[dustymabe]

The readme example to create a workitem is out of date now: c846ca3#diff-7bd4a925c695c2eb0eced3872b9b965fR197

It gives you this error:

[vagrant f24 almighty-core]$ ./bin/alm-cli create workitem --payload '{"type": "1" , "name": "some name", "fields": { "system.owner": "tmaeder", "system.state": "open" }}' -H localhost:8080
2016/09/06 20:18:11 [INFO] started id=J5v/kihB POST=http://localhost:8080/api/workitems
2016/09/06 20:18:11 [INFO] started req_id=w7m9vmdnwz-14 POST=/api/workitems from=::1 ctrl=WorkitemController action=Create
2016/09/06 20:18:11 [INFO] payload req_id=w7m9vmdnwz-14 raw={"fields":{"system.owner":"tmaeder","system.state":"open"},"type":"1"}
2016/09/06 20:18:11 loading work item type 1
2016/09/06 20:18:11 not found, res={{0001-01-01 00:00:00 +0000 UTC 0001-01-01 00:00:00 +0000 UTC <nil>}  0  map[]}
2016/09/06 20:18:11 [INFO] completed req_id=w7m9vmdnwz-14 status=400 error=N8DjLctB bytes=99 time=1.602504ms
2016/09/06 20:18:11 [INFO] completed id=J5v/kihB status=400 time=6.633171ms
error: 400: {"id":"N8DjLctB","code":"bad_request","status":400,"detail":"Bad value for parameter 'type': '1'"}

NOTE: the core api server was running in the background so the output is intermixed.

Aslak pointed me to a correct example: https://github.com/almighty/almighty-core/blob/master/examples/create_workitem.json

let's fix the readme

[aslakknutsen]

This will be fixed in #195