chore: add 20th anniversary event

Author: trovster

src/content/events/2025-10-18-20th-anniversary.md

@@ -0,0 +1,14 @@
+---
+title: 20th Anniversary
+date: 2025-10-18T17:00:00Z
+location:
+  postal-code: B2 5NY
+summary: Join us and celebrate the 20th Anniversary of the Multipack.
+start: 2025-10-18T17:00:00Z
+end: 2025-10-18T21:00:00Z
+---
+It has been **20 years** since the first meetup of the Multipack.
+
+Join us from 6pm in one of our original haunts, the classy Old Joint Stock in Birmingham city centre, conveniently located near New Street and Moor Hill for that easy access by train.
+
+There is nothing on the agenda apart from celebrating the milestone and reminiscing over a pint and some food.