Add RBQ Conf 2026 (ruby-conferences#1137)

Author: marcoroth

_data/conferences.yml

@@ -3176,6 +3176,14 @@
   cfp_close_date: 2025-06-30
   cfp_link: https://www.papercall.io/rubyconfth2026
 
+- name: RBQ Conf 2026
+  location: Austin, TX
+  start_date: 2026-03-31
+  end_date: 2026-03-31
+  date_precision: month
+  url: https://rbqconf.com
+  announced_on: 2025-07-17
+
 - name: Tropical on Rails 2026
   location: São Paulo, Brazil
   start_date: 2026-04-09