Bump cryptography to 42.0.2 and PyOpenSSL to 24.0.0

[ecerulm]

cryptography 41.0.6 has a moderate security vulnerability

https://github.com/urllib3/urllib3/security/dependabot/12

A flaw was found in the python-cryptography package. This issue may allow a remote attacker to decrypt captured messages in TLS servers that use RSA key exchanges, which may lead to exposure of confidential or sensitive data.

@dependabot has identified this in #3339 but it failed to update PyOpenSSL accordingly
hence this PR

Closes #3339

[ecerulm]

The vulnerability seems to affect only servers so in principle I guess that it does not really matter for urllib3.

Also I wonder if we should just use

cryptography>=42.0.0

instead of pinning a specific version like we do now.

PyOpenSSL 24.0.0 currently allows cryptography>=41.0.5,<43, so we need to force cryptography>=42.0.0 if we want to avoid pip resolving to cryptography==41.0.5
https://github.com/pyca/pyopenssl/blob/482b95ec4bbd5d9dbd37194517ffd8ab9acdeff7/setup.py#L96C13-L96C40

[pquentin]

Thanks! LGTM. Pinning avoids surprises and means there's one less thing to worry about when we see a test failing. The downside is indeed that we need to work to upgrade pins. We unfortunately can't use pip-compile because it only supports one Python version at at a time.