link python3 to python3 7

1Damn, Python is used throughout much of Ubuntu for system scripts and software,
2and software relies on having Python (and the commands to start Python)
3in a certain spot. do back then.
4
5rm /usr/bin/python3 
6ln -s /usr/bin/python3.7 /usr/bin/python3 
7
8# create alias in ~/.bash_aliases
9
10alias python3='/usr/bin/python3.7' 
11Scripts can then start with something like:
12
13#!/usr/bin/env python3