uses deprecated ssl.PROTOCOL_TLS #1670

_______________________________________________________________________ test_default_default_headers _______________________________________________________________________

    @pytest.mark.asyncio
    async def test_default_default_headers():
        config = Config(app=app, loop="asyncio", limit_max_requests=1)
        async with run_server(config):
>           async with httpx.AsyncClient() as client:

tests/test_default_headers.py:18: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
venv/lib/python3.10/site-packages/httpx/_client.py:1242: in __init__
    self._transport = self._init_transport(
venv/lib/python3.10/site-packages/httpx/_client.py:1285: in _init_transport
    ssl_context = create_ssl_context(verify=verify, cert=cert, trust_env=trust_env)
venv/lib/python3.10/site-packages/httpx/_config.py:49: in create_ssl_context
    return SSLConfig(
venv/lib/python3.10/site-packages/httpx/_config.py:73: in __init__
    self.ssl_context = self.load_ssl_context()
venv/lib/python3.10/site-packages/httpx/_config.py:85: in load_ssl_context
    return self.load_ssl_context_verify()
venv/lib/python3.10/site-packages/httpx/_config.py:122: in load_ssl_context_verify
    context = self._create_default_ssl_context()
venv/lib/python3.10/site-packages/httpx/_config.py:156: in _create_default_ssl_context
    context = SSL.SSLContext(ssl.PROTOCOL_TLS)
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cls = <class 'ssl.SSLContext'>, protocol = ssl.PROTOCOL_TLS, args = (), kwargs = {}

    def __new__(cls, protocol=None, *args, **kwargs):
        if protocol is None:
            warnings.warn(
                "ssl module: "
                "SSLContext() without protocol argument is deprecated.",
                category=DeprecationWarning,
                stacklevel=2
            )
            protocol = PROTOCOL_TLS
>       self = _SSLContext.__new__(cls, protocol)
E       DeprecationWarning: ssl module: PROTOCOL_TLS is deprecated

/usr/lib/python3.10/ssl.py:501: DeprecationWarning