readme: requirements

Author: uggedal

README.md

@@ -4,4 +4,10 @@ void-updates
 Script intended to be run daily via cron for finding upstream updates
 to [void-packages][]. This is just a wrapper around `./xbps-src update-check`.
 
+Requirements
+------------
+
+* xbps
+* git
+
 [void-packages]: https://github.com/voidlinux/void-packages