chore: set banner startTime to 18 May

Signed-off-by: thisisobate <obasiuche62@gmail.com>

Author: thisisobate

data/announcements/scheduled.yaml

@@ -325,7 +325,7 @@ announcements:
     </a>
 
 - name: KubeCon 2026 India
-  startTime: 2026-05-15T00:00:00
+  startTime: 2026-05-18T00:00:00
   endTime: 2026-06-19T18:00:00
   style: >-
     background: linear-gradient(90deg, #eeb32d 0%, #f5d4a1 100%);