1、首先安装 EPEL 源：
yum install epel-release
2、安装 REMI 源：
yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm
3、安装 PHP7.3：
yum install -y php73-php-fpm php73-php-cli php73-php-bcmath php73-php-gd php73-php-json php73-php-mbstring php73-php-mcrypt php73-php-mysqlnd php73-php-opcache php73-php-pdo php73-php-pecl-crypto php73-php-pecl-mcrypt php73-php-pecl-geoip php73-php-recode php73-php-snmp php73-php-soap php73-php-xmll
4、查看版本
php73 -v
