update node js version in ubuntu 18.06 code example

Example 1: how to update node in ubuntu 18.04

# Using Ubuntu
curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
sudo apt-get install -y nodejs

Example 2: how to update node in ubuntu 18.04

sudo npm cache clean -f
sudo npm install -g n
sudo n stable