add php7.4 to ubuntu code example
Example 1: install php 7.3 ubuntu
sudo apt install php7.3-cli php7.3-fpm php7.3-json php7.3-pdo php7.3-mysql php7.3-zip php7.3-gd php7.3-mbstring php7.3-curl php7.3-xml php7.3-bcmath php7.3-json
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