WINDOWS-1252 encoding name case mismatch in Nixpkgs

[mweinelt]

We packaged httpx2 in nixpkgs and the upgrade to 2.4.0 introduced checks for the WINDOWS-1252 encoding. In nixpkgs that name is capitalized as Windows-1252. E.g.:

___________________ test_client_decode_text_using_autodetect ___________________

    def test_client_decode_text_using_autodetect() -> None:
        # Ensure that a 'default_encoding=autodetect' on the response allows for
        # encoding autodetection to be used when no "Content-Type: text/plain; charset=..."
        # info is present.
        #
        # Here we have some french text encoded with WINDOWS-1252, rather than UTF-8.
        # The curly quotes and em dash occupy bytes 0x80-0x9F, which are control
        # characters in ISO-8859-1, so the encoding is unambiguously WINDOWS-1252.
        text = (
            "Non-seulement Despréaux ne se trompait pas — mais de tous les écrivains "
            "que la France a produits, sans excepter Voltaire lui-même, imprégné de "
            "l’esprit anglais par son séjour à Londres, c’est incontestablement "
            "“Molière” ou Poquelin qui reproduit avec l’exactitude la plus vive et la "
            "plus complète le fond du génie français."
        )
    
        def cp1252_but_no_content_type(request: httpx2.Request) -> httpx2.Response:
            content = text.encode("WINDOWS-1252")
            return httpx2.Response(200, content=content)
    
        transport = httpx2.MockTransport(cp1252_but_no_content_type)
        with httpx2.Client(transport=transport, default_encoding=autodetect) as client:
            response = client.get("http://www.example.com")
    
            assert response.status_code == 200
            assert response.reason_phrase == "OK"
>           assert response.encoding == "WINDOWS-1252"
E           AssertionError: assert 'Windows-1252' == 'WINDOWS-1252'
E             
E             - WINDOWS-1252
E             + Windows-1252

tests/httpx2/client/test_client.py:434: AssertionError

I wouldn't know where these names originate. Would you be open to just making these matches case-insensitive?

[Kludex]

Yes, sure. Can you please open a PR? Happy to make your life easier.

[mweinelt]

It looks like we overlooked the chardet 6.0.0.post1 bump, which explains this mismatch. Sorry for the noise.