Python Docker Base image problems

[RoryMMMM]

I run into issues when building the python docker container. It seems that the repo for jessie images has moved so doing some apt-get install tasks fail. This can be fixed by changing the base image to python3.6-stretch

[RoryMMMM]

https://unix.stackexchange.com/questions/443192/debian-8-apt-get-update-showing-404-not-found