Prep 6 release (#24)

* prep 6 release

* force urllib3 update

* add setuptools and wheel to dev packages

Author: cscorley

Pipfile

@@ -8,8 +8,15 @@ nose = "*"
 flake8 = "*"
 tox = "*"
 twine = "*"
+black = "*"
+urllib3 = ">=1.24.2"
+setuptools = "*"
+wheel = "*"
 
 [packages]
 
 [requires]
 python_version = "3.7"
+
+[pipenv]
+allow_prereleases = true