python 3.6 setup

1.添加python3.6安装包,并且安装

sudo apt-get install software-properties-common

2.下载python3.6

sudo add-apt-repository ppa:jonathonf/python-3.6
sudo apt-get update
sudo apt-get install python3.6

2.修改系统默认python版本为3.6，并更新

cd /user/bin
rm python
ln -s python3.6m python

python pip install --upgrade pip