Update README.md for socks5h

[zhenjunMa]

• Use socks5h:// if you want DNS resolution to happen through the SOCKS5 proxy, ensuring better privacy and avoiding DNS leakage.
• Use socks5:// if you're okay with DNS resolution happening locally on the client.

This distinction is important when using tools like curl, networking libraries, or applications that rely on proxies.

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I found that requests often fail because of this detail, and I just encountered it again. Let's add it to the documentation.

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Additionally, I think this SOCKS proxy feature is very useful, but the current version on PyPI doesn't include this feature. If possible, could you release a new version to PyPI?😄