Add guidance for Amazon Linux, RedHat Enterprise Linux, wrt OpenSSL versions

[sethmlarson]

This error has been cropping up in a few GitHub issues/comments:

ImportError: urllib3 v2.0 only supports OpenSSL 1.1.1+, currently the 'ssl' module is compiled with OpenSSL 1.0.2k-fips  26 Jan 2017. See: https://github.com/urllib3/urllib3/issues/2168

There's likely some additional guidance we can give folks that are receiving this error in our v2 migration guide:

• Create a separate section for this issue and how to mitigate it
• Have this error message verbatim in the migration guide under the section
• Mention specifically Amazon Linux and RHEL, but also other platforms we're aware of
• Recommend to users to figure out if they can upgrade their OpenSSL version or platform to get onto an OpenSSL release which is receiving security releases
• If they can't, then they need to pin urllib3<2 until they do.

[cmawhorter]

on amazon linux 2, openssl 1.1 is available as a different package named openssl11

this worked for me w/pyenv:

1. remove (or don't install) openssl-devel
2. yum install openssl11 openssl11-devel
3. pyenv install 3.9