Update Wagtail Space dates

README.md

@@ -229,7 +229,7 @@ Awesome Wagtail [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38
 
 - [Dutch Wagtail Meetup](http://www.meetup.com/Dutch-Wagtail-Meetup/) - This is a group for anyone interested in working and developing with Wagtail.
 - [Wellington Wagtail CMS Meetup](http://www.meetup.com/Wellington-Wagtail-CMS-Meetup/) - The first Wagtail CMS meetup in New Zealand!
-- [Wagtail Space](http://www.wagtail.space/) - Wagtail training sessions, Wagtail (lightning) talks and a Wagtail sprint. From March 13st until 15th 2019, Wagtail Space takes place in Arnhem, The Netherlands.
+- [Wagtail Space](http://www.wagtail.space/) - Wagtail training sessions, Wagtail (lightning) talks and a Wagtail sprint. From March 13th until 15th 2019, Wagtail Space takes place in Arnhem, The Netherlands.
 
 ## Open-source sites