change php version centos code example

Example 1: change php version ubuntu

//In ubunutu
Default PHP 7.1 is set on your system and you need to switch to PHP 5.6

$ sudo a2dismod php7.1
$ sudo a2enmod php5.6
$ sudo service apache2 restart
  
sudo update-alternatives --set php /usr/bin/php5.6

Example 2: debian php switch version

// Apache:
sudo a2dismod php5.6 php7.1 php7.0   ## Shows error for modules not installed 
sudo a2enmod php7.4
sudo service apache2 restart

// In case of issues disabling some modules use the following syntax
sudo a2dismod mpm_prefork
//--------------------------------------------------------------

// Command Line:
sudo update-alternatives --set php /usr/bin/php7.4
sudo update-alternatives --set phar /usr/bin/phar7.4
sudo update-alternatives --set phar.phar /usr/bin/phar.phar7.4
sudo update-alternatives --set phpize /usr/bin/phpize7.4
sudo update-alternatives --set php-config /usr/bin/php-config7.4