update base python to 3.8

Author: auvipy

docker/base/Dockerfile

@@ -1,7 +1,7 @@
 # Copyright (C) 2019 Sebastian Pipping <[email protected]>
 # Licensed under the BSD License (3 clause, also known as the new BSD license)
 
-FROM python:3.7
+FROM python:3.8
 
 ENV PATH=${PATH}:/root/.local/bin