fixup! update changelog and readme

Author: roycaihw

CHANGELOG.md

@@ -7,7 +7,6 @@
 - The Python client will be generated by openapi-generator, with the following breaking changes [kubernetes-client/gen#97](https://github.com/kubernetes-client/gen/pull/97)
 - `kubernetes.client.apis` package is renamed to `kubernetes.client.api`
 - `kubernetes` package code now uses absolute import instead of relative import
-- API requests won't have `Content-Type` specified in HTTP headers
 - The `swagger_types` attribute in all models is renamed to `openapi_types`
 - Python3.4 is no longer supported [kubernetes-client/python#807](https://github.com/kubernetes-client/python/pull/807)