Merge pull request kubernetes-client#2105 from jsaalfeld/urllib3-version-fix

Setting upper version bound for urllib3

Author: k8s-ci-robot

requirements.txt

@@ -9,4 +9,4 @@ websocket-client>=0.32.0,!=0.40.0,!=0.41.*,!=0.42.* # LGPLv2+
 requests # Apache-2.0
 requests-oauthlib # ISC
 oauthlib>=3.2.2 # BSD
-urllib3>=1.24.2  # MIT
+urllib3>=1.24.2,<2.0  # MIT