[test] Add a "version" to cubicweb_mycube/__pkginfo__.py Starting from Python 3.5, unittest_cwctl.py::CubicWebCtlTC.test_list() would fail without this.

addressbook
basket
blog
book
calendar
comment
company
email
file
folder
i18ncontent
keyword
link
mailinglist
person
tag
timeseries
vcsfile