Cherry-pick base64 padding fix from python-base

Author: roycaihw

CHANGELOG.md

@@ -2,6 +2,9 @@
 **Security Fix:**
 - Bump urllib3 version to pick up security fix for CVE-2019-11324 [kubernetes-client/python#897](https://github.com/kubernetes-client/python/pull/897)
 
+**Bug Fix:**
+- Fix base64 padding for kube config [kubernetes-client/python-base#79](https://github.com/kubernetes-client/python-base/pull/79)
+
 # v9.0.0
 **Bug Fix:**
 - Add fieldSelector parameter to list/watch methods in custom objects spec [kubernetes-client/gen#106](https://github.com/kubernetes-client/gen/pull/106)