BalticRuby 2025 link points to the main site (ruby-conferences#680)

Co-authored-by: Sergy S. <sergy@cybergizer.com>

Author: Sergyenko

_data/conferences.yml

@@ -2782,7 +2782,7 @@
   start_date: 2025-06-30
   end_date: 2025-06-30
   date_precision: month
-  url: https://balticruby.org/balticruby2025
+  url: https://balticruby.org
   twitter: balticruby
   mastodon: https://ruby.social/@balticruby