Update CAST 2026 status: add Early Bird Registration link (#875)

* Initial plan

* Update CAST 2026 status to include Early Bird Registration link

Agent-Logs-Url: https://github.com/TestingConferences/testingconferences.github.io/sessions/28a59592-40e7-4b7a-967b-8c68578ca591

Co-authored-by: ckenst <6896787+ckenst@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ckenst <6896787+ckenst@users.noreply.github.com>

Author: Copilot

_data/current.yml

@@ -185,7 +185,7 @@
   dates: "August 3-5, 2026"
   url: https://associationforsoftwaretesting.org/conference/?utm_source=testingconferences
   twitter: AST_News
-  status: <a href="https://sessionize.com/association-for-software-testing-cast/" target="_blank">CFP is Open</a> until May 31, 2026
+  status: <a href="https://sessionize.com/association-for-software-testing-cast/" target="_blank">CFP is Open</a> until May 31, 2026. <a href="https://associationforsoftwaretesting.org/conference/cast-2026/cast-2026-packages-pricing/?utm_source=testingconferences" target="_blank">Early Bird Registration is Open</a> until June 1, 2026
 
 - name: Testing Talks Sydney 2026
   location: Sydney, Australia