add Japan regional Ruby events (#53)

- https://regional.rubykaigi.org/tokyo13/
- https://regional.rubykaigi.org/kansai09/
- https://regional.rubykaigi.org/nagoya05/

Author: koxya

demo/rsn_events_bot/events.yml

@@ -68,10 +68,18 @@ events:
     date: "2026-06-25"
     location: "Brighton, England, United Kingdom"
 
+  - name: "Tokyo RubyKaigi 13"
+    date: "2026-06-27"
+    location: "Tokyo, Japan"
+
   - name: "RubyConf 2026"
     date: "2026-07-14"
     location: "Las Vegas, NV, United States"
 
+  - name: "Kansai RubyKaigi 09"
+    date: "2026-07-18"
+    location: "Otsu, Shiga, Japan"
+
   - name: "RubyConf Africa 2026"
     date: "2026-08-21"
     location: "Nairobi, Kenya"
@@ -84,6 +92,10 @@ events:
     date: "2026-09-16"
     location: "Brno, Czechia"
 
+  - name: "Nagoya RubyKaigi 05"
+    date: "2026-09-19"
+    location: "Nagoya, Aichi, Japan"
+
   - name: "Rails at Scale Summit 2026"
     date: "2026-09-22"
     location: "Austin, TX, United States"