remove requests and urllib3 from install_requires

[sjhewitt]

Please answer these questions before submitting your pull requests. Thanks!

1. What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-926289: Why is urllib3 both vendored and marked as a dependency? #1743

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
   • I am adding new logging messages
   • I am adding a new telemetry message
   • I am modifying authorization mechanisms
   • I am adding new credentials
   • I am modifying OCSP code
   • I am adding a new dependency

3. Please describe how your code solves the related issue.

requests and urllib3 are vendored, so there is no need to specify them as dependencies.

[timostrunk]

It would be really great, if this was pulled. Currently snowflake-connector-python cannot be used in a production setting, because it incurs security issues by both forcing a vulnerable urllib3 and packaging a vulnerable urllib3 by itself.
The OCSP requirement from the internal SF security team must be re-evaluated. It has lead to many such situations in the past.

[sfc-gh-mkeller]

I'm sorry, but keeping requests will be necessary. Please see my explanation in #1743