chore: Update minimum Python version in README

Author: rmkeezer

README.md

@@ -7,9 +7,8 @@
 This project contains core functionality required by Python code generated by the IBM Cloud OpenAPI SDK Generator
 (openapi-sdkgen).
 
-# Notice
-Support for Python versions 2.x and versions <= 3.4 is deprecated and will be officially dropped in the next major release,
-which is expected to be end of December, 2019.
+# Python Version
+The current minimum Python version supported is 3.5.3.
 
 ## Installation