Update deadline (#470)

* Update deadline

* Remove deadline

Author: jaclark5

pages/ugm2025.md

@@ -37,7 +37,7 @@ You can expect:
 
 ## Registration
 
-Register by **July 15, 2025** (midnight anywhere on Earth):
+~~Register by **July 15, 2025**~~ Registration is continuing on a rolling basis until participation limits are reached, at which point this page will be updated.
 
 <a href="https://forms.gle/bPvVTMpzBkyCRtNA7" target="_blank" style="background:#FF9200;padding:10px;margin:10px 0px;text-align:center;text-decoration:none;font-size:16pt;color:#000000;display:inline-block;border-radius:3px">Register</a>