Use typing_extensions.deprecated

[MartinThoma]

I've just noticed https://peps.python.org/pep-0702/ by using model.json() of a pydantic model object. The json() method is deprecated in pydantic 2.0.0 and Visual Studio Code made it visually pretty clear.

We should also use that, to give developers the hint.

This is mostly a note to myself :-)

[MartinThoma]

• https://github.com/python/typing_extensions/blob/main/CHANGELOG.md#release-450-february-14-2023 -> typing-extensions==4.5.0 would be required
• https://pypi.org/project/typing-extensions/4.5.0/ -> Seems only to be available for Python 3.7+
• See Drop Python 3.6 support #2005

[stefan6419846]

I can only speak for PyCharm, but using the "old" way with warnings.warn("deprecated", DeprecationWarning) correctly marks the corresponding methods as well.