Restrict version of UrlLib3 < 2 (#57)

Author: Denis-Averin

README.md

@@ -92,7 +92,7 @@ pprint(response)
 ## Requirements
 
 - six >= 1.10
-- urllib3 >= 1.15.1
+- urllib3 >= 1.21.1, <2.0
 
 ## Licensing
 

requirements.txt

@@ -1,4 +1,4 @@
 certifi >= 2017.4.17
 python-dateutil >= 2.1
 six >= 1.10
-urllib3 >= 1.23
+urllib3 >= 1.21.1, <2.0

setup.py

@@ -37,7 +37,7 @@
 # prerequisite: setuptools
 # http://pypi.python.org/pypi/setuptools
 
-REQUIRES = ["certifi>=2017.4.17", "python-dateutil>=2.1", "six>=1.10", "urllib3>=1.23"]
+REQUIRES = ["certifi>=2017.4.17", "python-dateutil>=2.1", "six>=1.10", "urllib3 >= 1.21.1, <2.0"]
 
 here = os.path.abspath(os.path.dirname(__file__))