BUGFIX: Make  dev collection and neos/flow dependencies match
BUGFIX: Make  dev collection and neos/flow dependencies match

Fixes the doctrine/migrations dependency (again) and adds ext-xml to
the neos/flow dependencies so updating the collection manifest picks
it up correctly.

Fixes neos/neos-development-collection#2310
Related #1356

neos/flow,neos/flow,neos/flow,neos/flow