Dockerfile: update Ruby version from 3.1.6 to 3.2.8

kimihito · kimihito · commit 98e490e837a5 · 2025-05-17T16:28:25.000+09:00
diff --git a/Dockerfile b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:3.1.6
+FROM ruby:3.2.8
 
 ENV LANG C.UTF-8
 
