Remove requirements upper limitation and start using upper constraints

The some of the flake8 requirement can not be satisfied, so
the test results is raising an error:

    Traceback (most recent call last):
      File "/ci-log-processing/.tox/pep8/bin/flake8", line 7, in <module>
        sys.exit(main())
                 ^^^^^^
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/main/cli.py", line 22, in main
        app.run(argv)
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/main/application.py", line 363, in run
        self._run(argv)
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/main/application.py", line 350, in _run
        self.initialize(argv)
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/main/application.py", line 330, in initialize
        self.find_plugins(config_finder)
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/main/application.py", line 153, in find_plugins
        self.check_plugins = plugin_manager.Checkers(local_plugins.extension)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/plugins/manager.py", line 356, in __init__
        self.manager = PluginManager(
                       ^^^^^^^^^^^^^^
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/plugins/manager.py", line 238, in __init__
        self._load_entrypoint_plugins()
      File "/ci-log-processing/.tox/pep8/lib/python3.12/site-packages/flake8/plugins/manager.py", line 254, in _load_entrypoint_plugins
        eps = importlib_metadata.entry_points().get(self.namespace, ())
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    AttributeError: 'EntryPoints' object has no attribute 'get'

After updating packages to newer version, flake8 seems to be working
normally.

Co-Authored-By: Slawek Kaplonski <skaplons@redhat.com>
Change-Id: I27d36a21fa57619d3fd41f01b83f91990708089b
Signed-off-by: Daniel Pawlik <dpawlik@redhat.com>

requirements.txt

@@ -1,6 +1,6 @@
-pbr>=1.6         # Apache-2.0
-requests<2.27    # Apache-2.0
-PyYAML<6.1       # MIT
+pbr>=1.6               # Apache-2.0
+requests>=2.32.3       # Apache-2.0
+PyYAML                 # MIT
 tenacity
 opensearch-py<=1.0.0   # Apache-2.0
 ruamel.yaml

test-requirements.txt

@@ -1,6 +1,6 @@
-hacking<4.1.1    # Apache-2.0
-flake8<3.8.5
-pep8<1.7.2
-testtools<2.5.1  # MIT
-stestr<3.3       # Apache-2.0
-yamllint<1.26.4  # GPLv3
+hacking          # Apache-2.0
+flake8
+pep8
+testtools        # MIT
+stestr           # Apache-2.0
+yamllint         # GPLv3

tox.ini

@@ -3,8 +3,10 @@ envlist = linters,docs,py3
 
 [testenv]
 usedevelop = True
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/test-requirements.txt
 allowlist_externals = find
 commands =
   find . -type f -name "*.pyc" -delete