Aiorequestful

Added
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* :py:meth:`.AuthRequest.set_payload_type` and ``payload`` property to :py:class:`.AuthRequest`.
This allows for payload type switching for each requests.
This is to solve an issue where some OAuth providers require the payload in either the body or query of the request
depending on the providers specification.

Removed
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* ``_param_key`` class attribute in :py:class:`.OAuth2Authoriser` now allows for control over for child classes
Support for switching the payload handling of requests is now handled solely by :py:class:`.AuthRequest`.

Changed
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* :py:class:`.OAuth2Authoriser` now allows for control over params key for child classes
via the ``_param_key`` class attribute.
This now supports delivering params via either the query or body or the request.

Fixed
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* :py:class:`.AuthorisationCodeFlow` now correctly picks up the returned state value from the redirect URL
even if it also contains the HTTP version

Changed
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* Handle no response as a retry using the retry timer in :py:class:`.RequestHandler`

Fixed
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* Drop debug print statement

Fixed
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* Replace ``classmethod`` + ``property`` decorators with custom :py:class:`.classproperty` decorator
to fix issues in Python v3.13