fix: submission date wrong

Author: OebbJan

content/_index.md

@@ -14,4 +14,4 @@ related_pages:
 Lassallestrasse 5. 
 1020 Wien
 
-Got an idea for a challenge? Become a challenge owner and [submit your challenge until March 10](https://share.openrailassociation.org/apps/forms/s/j5T8b5XocATQj5Rik5rcN5mH)!
+Got an idea for a challenge? Become a challenge owner and [submit your challenge until March 19](https://share.openrailassociation.org/apps/forms/s/j5T8b5XocATQj5Rik5rcN5mH)!