Update abstract submission deadline for JuMP-dev (#169)

Author: odow

_posts/2024-09-26-jump_dev_2025.md

@@ -37,8 +37,8 @@ excursion. The schedule is subject to change at any time.
 ## Key dates
 
  * October 2024: [talk submissions open](https://forms.gle/SzbqwzfsRNW97PZt5)
- * February 28 2025: talk submissions close
- * March 31 2025: talk acceptance notifications
+ * March 31 2025: talk submissions close
+ * April 30 2025: talk acceptance notifications
  * November 17--20 2025: JuMP-dev 2025
 
 ## How do I attend?