Update default 7.3-fpm version

Author: vfalies

.env.dist

@@ -16,7 +16,7 @@ WEB_PORT=80
 WEBSSL_PORT=443
 
 # PHP version (See https://github.com/vfalies/EnvDev/blob/master/docs/configuration.md for all possible values)
-PHP_VERSION=7.2-fpm
+PHP_VERSION=7.3-fpm
 
 # Database
 # Possible value: mysql / mariadb / mongodb