Update pricai 2026 (#1370)

* Add PRICAI 2026 deadline

Add PRICAI 2026 submission deadline and conference information.

Official website:
https://2026.pricai.org/

* Update pricai.yml

Author: hala-yh

conference/AI/pricai.yml

@@ -23,3 +23,11 @@
       timezone: UTC-12
       date: Nov 17-21, 2025
       place: Wellington, New Zealand
+    - year: 2026
+      id: pricai2026
+      link: https://2026.pricai.org/
+      timeline:
+        - deadline: '2026-06-13 23:59:59'
+      timezone: UTC-12
+      date: Nov 17-20, 2026
+      place: Guangzhou, China