Add Ruby Zagreb - July RubyZG drinkup (ruby-conferences#1129)

Co-authored-by: marcoroth <6411752+marcoroth@users.noreply.github.com>

Author: github-actions[bot]

_data/meetups.yml

@@ -7027,6 +7027,13 @@
   end_time: 19:00:00 CST
   url: https://www.meetup.com/rails-taiwan/events/qxfvjkyhckbfc
 
+- name: Ruby Zagreb - July RubyZG drinkup
+  location: Zagreb, Croatia
+  date: 2025-07-24
+  start_time: 18:00:00 CEST
+  end_time: 20:00:00 CEST
+  url: https://www.meetup.com/rubyzg/events/309352017
+
 - name: Toronto Ruby - July 2025 Edition
   location: Toronto, Canada
   date: 2025-07-24