Merge pull request rails#53005 from fkmy/fix-migration-version-in-guide

[ci-skip][docs] Fix version of the migration in the guide to the current Rails version

Author: kamipo

guides/source/active_record_postgresql.md

@@ -102,7 +102,7 @@ NOTE: You need to enable the `hstore` extension to use hstore.
 
 ```ruby
 # db/migrate/20131009135255_create_profiles.rb
-class CreateProfiles < ActiveRecord::Migration[7.0]
+class CreateProfiles < ActiveRecord::Migration[8.0]
   enable_extension 'hstore' unless extension_enabled?('hstore')
   create_table :profiles do |t|
     t.hstore 'settings'

guides/source/association_basics.md

@@ -3137,7 +3137,7 @@ Although the `:counter_cache` option is specified on the model with the
 `books_count` column to the `Author` model:
 
 ```ruby
-class AddBooksCountToAuthors < ActiveRecord::Migration[6.0]
+class AddBooksCountToAuthors < ActiveRecord::Migration[8.0]
   def change
     add_column :authors, :books_count, :integer, default: 0, null: false
   end