Bump cheroot from 8.6.0 to 9.0.0 (#1903)

* Bump cheroot from 8.6.0 to 9.0.0

Bumps [cheroot](https://github.com/cherrypy/cheroot) from 8.6.0 to 9.0.0.
- [Release notes](https://github.com/cherrypy/cheroot/releases)
- [Changelog](https://github.com/cherrypy/cheroot/blob/main/CHANGES.rst)
- [Commits](https://github.com/cherrypy/cheroot/compare/v8.6.0...v9.0.0)

---
updated-dependencies:
- dependency-name: cheroot
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update cheroot==9.0.0

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

[skip ci]

lib/cheroot/test/test_cli.py

@@ -4,11 +4,8 @@
 
    cli
 """
-# -*- coding: utf-8 -*-
-# vim: set fileencoding=utf-8 :
 import sys
 
-import six
 import pytest
 
 from cheroot.cli import (
@@ -69,12 +66,6 @@ def wsgi_app(monkeypatch):
     app = WSGIAppMock()
     # patch sys.modules, to include the an instance of WSGIAppMock
     # under a specific namespace
-    if six.PY2:
-        # python2 requires the previous namespaces to be part of sys.modules
-        #   (e.g. for 'a.b.c' we need to insert 'a', 'a.b' and 'a.b.c')
-        # otherwise it fails, we're setting the same instance on each level,
-        # we don't really care about those, just the last one.
-        monkeypatch.setitem(sys.modules, 'mypkg', app)
     monkeypatch.setitem(sys.modules, 'mypkg.wsgi', app)
     return app