urllib3 method API Change

[THWiseman]

The urllib3 library (part of requests, which getm depends on) renamed the parameter method_whitelist to allowed_methods in order to be more racially inclusive. The method_whitelist parameter is no longer supported by urllib3, and was finally removed two weeks ago after its deprecation period ended. See changelog here and documentation here.

getm no longer works when installed with pip, since http.py references a parameter that no longer exists in the library. I recommend that http.py be updated to use the correct parameter name:

default_retry = Retry(total=10,
                      status_forcelist=[429, 500, 502, 503, 504],
                      allowed_methods=["HEAD", "GET"])

Pinning an older version of urllib3 is also a potential fix, but that seems less ideal than simply updating the method.

I'd be happy to submit a PR with the updated method if that's helpful. I'm also part of DataBiosphere, but can't currently push to this repo.