[test] Use cubicweb-file < 2.0.0
From version 2.0.0, cubicweb-file moved to new-style layout (Python
package) but we still expect it to be an old-style cube in CubicWeb's
tests (WebconfigTC in web/test/unittest_webconfig.py).
Document: cubicweb-doc
Title: CubicWeb Documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/python-cubicweb-documentation/html/index.html
Files: /usr/share/doc/python-cubicweb-documentation/html/*