Fix tests with tox and GitLab CI
- Use a new test case class (as the old one was removed from CW)
- Execute GitLab CI only in Python 3 as Python 2 support was already removed in tox
- Add missing requirements for testing
- Define a specific Python version, because logilab-common is
currently broken with Python 3.8 and above, because
cgi.escape
has been removed.
Edited by Nicola Spanti