add php repository code example

Example 1: ubuntu install php

apt-get install php-pear php-fpm php-dev php-zip php-curl php-xmlrpc php-gd php-mysql php-mbstring php-xml libapache2-mod-php

Example 2: install php 7.4 ubuntu

sudo apt update
sudo apt install php php-cli php-fpm php-json php-pdo php-mysql php-zip php-gd  php-mbstring php-curl php-xml php-pear php-bcmath

Example 3: install php 7.1 on ubuntu 18.04

sudo apt install software-properties-commonsudo add-apt-repository ppa:ondrej/php