Update requirements.rst (#747)

On stock Debian 9.9, "apt-get install php-xml" is needed to get anything to load. Here is the error you get without it: (Extension DOM is required. in /var/www/html/vendor/symfony/config/Util/XmlUtils.php:50)
2019-07-17 12:49:14 -04:00 · 2019-07-17 12:49:14 -04:00 · fc5110b174
parent 60604c5ec4
commit fc5110b174
1 changed files with 2 additions and 1 deletions
--- a/docs/requirements.rst
+++ b/docs/requirements.rst
@ -8,4 +8,5 @@ Requirements
 * For PHP5: 5.5.9+
 * For PHP7: 7.0.8+
 * PHP cURL package
-* PHP PDO mysql driver
+* PHP PDO mysql driver
+* PHP XML package