tests/test_config.py::test_load_ssl_with_keylog failure with PyPy3.10

[mgorny]

Looks like the test is using API that's not implemented in PyPy3.10;

$ pytest tests/test_config.py::test_load_ssl_with_keylog
========================================================= test session starts =========================================================
platform linux -- Python 3.10.14[pypy-7.3.17-final], pytest-8.3.3, pluggy-1.5.0
rootdir: /tmp/httpx
configfile: pyproject.toml
plugins: anyio-4.6.2.post1
collected 1 item                                                                                                                      

tests/test_config.py F                                                                                                          [100%]

============================================================== FAILURES ===============================================================
______________________________________________________ test_load_ssl_with_keylog ______________________________________________________

monkeypatch = <_pytest.monkeypatch.MonkeyPatch object at 0x00007ff9b70876a8>

    def test_load_ssl_with_keylog(monkeypatch: typing.Any) -> None:
        monkeypatch.setenv("SSLKEYLOGFILE", "test")
        context = httpx.create_ssl_context()
>       assert context.keylog_filename == "test"
E       AttributeError: 'SSLContext' object has no attribute 'keylog_filename'

tests/test_config.py:26: AttributeError
========================================================== 1 failed in 0.35s ==========================================================

I've filed a bug for PyPy too: pypy/pypy#5141.

[mgorny]

PyPy is fixed now, and the fix will be in the next release. Given it's just a test failure, I think we're good.