urllib new version v2.6.0 breaks the RESTResponse

[ogeber-pass]

Hello,

in the latest version of urllib (v.2.6.0) the getheaders() method has been replaced with headers() (see here)

This dependency update breaks the following lines

I guess the fix would be something like

class RESTResponse(io.IOBase):

    def __init__(self, resp):
        self.urllib3_response = resp
        self.status = resp.status
        self.reason = resp.reason
        self.data = resp.data

    def getheaders(self):
        """Returns a dictionary of the response headers."""
        return self.urllib3_response.headers()

    def getheader(self, name, default=None):
        """Returns a given response header."""
        return self.urllib3_response.headers.get(name, default)

I would be glad to contribute but i didn't manage to run tests locally to check it didn't break other part of the code, so I didn't push my branch

Regards