Merge pull request rails#52920 from hachi8833/fix_ar_basic

[ci-skip][docs] Add missing migration version to Active Record Basic guide

Author: kamipo

guides/source/active_record_basics.md

@@ -213,7 +213,7 @@ and results in this:
 # Columns `created_at` and `updated_at` are added by `t.timestamps`.
 
 # db/migrate/20240220143807_create_books.rb
-class CreateBooks < ActiveRecord::Migration
+class CreateBooks < ActiveRecord::Migration[8.0]
   def change
     create_table :books do |t|
       t.string :title