Fix for Flask 2.3.0

Recently, Flask and Werkzeug updated to version 2.3.0 which broke the token authentication in Flask-HTTPAuth. After my careful look in the library and long search for the cause, I have discovered by due to the latest changes in Werkzeug's Authorization class, there are some problems with tokens. What I am looking into is: > Both classes have type, parameters, and token attributes. The token attribute supports auth schemes that use a single opaque token rather than key=value parameters, such as Bearer. > Neither class is a dict anymore, although they still implement getting, setting, and deleting auth[key] and auth.key syntax, as well as auth.get(key) and key in auth. I have successfully found the solution to this problem by changing how the token is preserved in the Authorization class. Formerly it was: ```py auth = Authorization(auth_type, {'token': token}) ``` After my consideration, I have come to the conclusion that changing it to the form below will fix the problem: ```py auth = Authorization(auth_type, token=token) ``` What I also changed was the method of retrieving the token from: ```py token = auth['token'] ``` to: ```py token = auth.token ``` In addition to my understanding, it's also the preferred way of setting, keeping and retrieving the token as of now. I have also updated all applicable tests (didn't find anything to change in examples or docs) so they use that method. I made every effort I could to not introduce any breaking change in a code, although I would recommend checking it once again to make sure everything is as it should be. Before committing I ran the tests with the latest versions of every package needed: | Test | Passed | |------|--------| |test_basic_custom_realm|OK| |test_basic_get_password|OK| |test_basic_hashed_password|OK| |test_basic_verify_password_async|OK| |test_basic_verify_password|OK| |test_digest_custom_realm|OK| |test_digest_get_password|OK| |test_digest_ha1_password|OK| |test_digest_no_qop|OK| |test_error_responses|OK| |test_multi_async|OK (Modified)| |test_multi|OK (Modified)| |test_roles_async|OK| |test_roles|OK| |test_token_async|OK| |test_token|OK|