Cannot import name 'PROTOCOL_TLS' from 'urllib3.util.ssl_'

Describe the bug

This issue is a direct follow-up from https://github.com/boto/botocore/issues/2562

When using older versions of urllib3 (often vendored), importing botocore.utils (or using botocore in any consideration) will fail.

Steps to reproduce

$ pip install --upgrade botocore==1.23.26
$ pip install --upgrade urllib3==1.22.0
$ python
>>> import botocore.utils
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/matthieu/.virtualenvs/reproavm/lib/python3.8/site-packages/botocore/utils.py", line 32, in <module>
    import botocore.httpsession
  File "/Users/matthieu/.virtualenvs/reproavm/lib/python3.8/site-packages/botocore/httpsession.py", line 10, in <module>
    from urllib3.util.ssl_ import (
ImportError: cannot import name 'PROTOCOL_TLS' from 'urllib3.util.ssl_' (/Users/matthieu/.virtualenvs/reproavm/lib/python3.8/site-packages/urllib3/util/ssl_.py)

Expected behavior

botocore should fallback to importing PROTOCOL_TLS from ssl.

[dmitryivashkin]

Still reproducible on python 3.8.13: botocore 1.27.70 urllib3 1.26.12

[drigoli]

Hi @stobrien89, I see this issue too.

awscli==1.22.26 botocore==1.23.26 urllib3==1.26.7

Statement on lines 10-12 in httpsession.py wants to import PROTOCOL_TLS from urllib3.util.ssl_, which does not exist there.

I can workaround by removing it from that statement and adding a separate statement, pulling from ssl. Though, I suspect the strategic direction is to level up on TLS version which would require more planning.