* Unpin Twisted, add a twisted-trunk tox env (without http2 for now).
* Hide the _setAcceptableProtocols import.
* Silence ScrapyClientContextFactory HTTP/1.0 warnings.
* Update ScrapyClientTLSOptions for unreleased Twisted.
* Add twisted-trunk to CI.
* Update for new changes in Twisted trunk.
* Xfail a test failing with newer Twisted.
* Test Twisted trunk with extra-deps, update the ALPN code.
* Cleanup.
* Fix typing.
* Update relevant type hints for Twisted trunk.
* Update test_no_context_sharing().
* Silence a weird mypy error.
* Update Twisted versions, unpin pyOpenSSL.
* Update a comment.
* Silence pylint.
* Make a factory fixture.
* Improve the _setAcceptableProtocols comment.
* Set OP_LEGACY_SERVER_CONNECT on new Twisted too.
* Add Twisted[http2] to extra-deps-pinned.
* Import some stuff from service_identity directly.
* Extract _log_tls().
* Sync validating IP addresses.
* Introduce _deps_compat.
* Deprecate getCertificateOptions().
* Deprecate ScrapyClientTLSOptions.
* Add pragma: no cover.
* verify=False and trustRoot=platformTrust() are the defaults.
* Improve docstrings for TLS classes.
* Deprecate AcceptableProtocolsContextFactory.
* Switch from DefaultOpenSSLContextFactory to CertificateOptions.
* Deprecate load_context_factory_from_settings().
* Remove the outdated warning about incompatible factories.
* Simplify _load_context_factory_from_settings().
* Make CertificateOptions and Context once per factory.
* pragma: no cover
* Switch TestEngineBase to mockserver.
* Split mockserver.py.
* Stop using WrappingFactory.
* Remove keyfile/certfile fields from TestHttpBase.
* Move webclient-only resources to test_webclient.py.
* Refactor MockServer.url().
* Migrate TestHttpBase to mockserver.
* Migrate TestSimpleHttpsBase to a separate mockserver.
* Rename TestHttpMockServerBase.
* Migrate TestHttpProxyBase to a separate mockserver.
* Refactor HTTP mockservers.
Andrey Rakhmatullin