Drop support for EOL Python 3.7 (#1065)

* Add python_requires to help pip

* Update supported versions in tox.ini

* Upgrade Python syntax with pyupgrade --py37-plus

* Bump GitHub Actions

* Add Python 3.11 and 3.12 to CI

* Remove six dependency

* Remove redundant dependencies

* Remove redudant Python 3.5 code

* Drop support for EOL Python 3.7

* Upgrade Python syntax with pyupgrade --py38-plus

* Update CHANGELOG

* More f-strings

---------

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>

tests/unit/test_oauth.py

@@ -1,20 +1,15 @@
-# -*- coding: utf-8 -*-
 import io
 import json
 import unittest
 
-import six.moves.urllib.parse as urllibparse
+import unittest.mock as mock
+import urllib.parse as urllibparse
 
 from spotipy import SpotifyOAuth, SpotifyImplicitGrant, SpotifyPKCE
 from spotipy.cache_handler import MemoryCacheHandler
 from spotipy.oauth2 import SpotifyClientCredentials, SpotifyOauthError
 from spotipy.oauth2 import SpotifyStateError
 
-try:
-    import unittest.mock as mock
-except ImportError:
-    import mock
-
 patch = mock.patch
 DEFAULT = mock.DEFAULT