Run CI also with Docker SDK for Python latest git release, and requests & urllib3 latest git releases

[felixfontein]

SUMMARY

Both can break due to changes in each other, and they can break the vendored Docker SDK for Python code.

Having them in CI would give us an early warning if that happens again.

(In case of requests, we would have found out about the breakage already in the beginning of March, when psf/requests#6655 got merged.)

ISSUE TYPE

• Bug Report

COMPONENT NAME

vendored Docker SDK for Python code; modules using Docker SDK for Python