Update requests in requirements.txt to avoid vulnerability

[Lohrer]

What does this change intend to accomplish?

I recently discovered https://github.com/micro-nova/AmpliPi/security/dependabot, and while I don't know anything about npm I took a look at the pip packages. Most of them aren't upgradeable until we get a new Python version, but requests can be upgraded to avoid https://github.com/micro-nova/AmpliPi/security/dependabot/4.

Checklist

• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Does your submission pass linting & tests? You can test on localhost using ./scripts/test

[rtertiaer]

our usage of the requests api appears to be explicitly the .get and .post methods, and some exception names. these are extremely unlikely to have broken within the 2.x series (if they semantically version) and mypy would catch that; i feel comfy shipping it with very little extra testing help on our part.