Remove local-oldest-requirements files (#8863)

This is part of https://github.com/certbot/certbot/issues/8787. I got a +1 from our packagers at major distros in https://github.com/certbot/certbot/issues/8761.

* remove local-oldest-requirements files

* fix tests

* fix some oldest tests

* list packages on one line in tox.ini

* add changelog entry

certbot-dns-gehirn/setup.py

@@ -14,8 +14,11 @@ install_requires = [
 
 if not os.environ.get('SNAP_BUILD'):
     install_requires.extend([
-        'acme>=0.31.0',
-        'certbot>=1.1.0',
+        # We specify the minimum acme and certbot version as the current plugin
+        # version for simplicity. See
+        # https://github.com/certbot/certbot/issues/8761 for more info.
+        f'acme>={version}',
+        f'certbot>={version}',
     ])
 elif 'bdist_wheel' in sys.argv[1:]:
     raise RuntimeError('Unset SNAP_BUILD when building wheels '