urllib3 update broke CI

[rmarren1]

https://pypi.org/project/urllib3/#history

The most up-to-date version is automatically installed when selenium is installed, but requests supports the previous version.

I'm working on a fix for #419 right now and I will just fix this as well.

[T4rk1n]

I fixed that problem in dcc tuesday plotly/dash-core-components#333, need to pin urllib3<=1.22

[rmarren1]

1.23 seems to work, was only <=1.22 working for you?

[T4rk1n]

I think that was the version listed as working in the requests issue.

[rmarren1]

Looks like requests just fixed it: https://github.com/requests/requests/blob/master/HISTORY.md