CI: Test Ruby 3.3

Add Ruby 3.3 to the most common Solidus setup
(Postgres, ActiveStorage, Rails 7.x) in order to
catch errors with latest Ruby 3.3

.circleci/config.yml

@@ -374,7 +374,7 @@ workflows:
           matrix: { parameters: { rails: ['7.0', '7.1'], ruby: ['3.0'], database: ['mysql'], paperclip: [true] } }
       - test_solidus:
           name: *name
-          matrix: { parameters: { rails: ['7.0', '7.1'], ruby: ['3.1'], database: ['postgres'], paperclip: [false] } }
+          matrix: { parameters: { rails: ['7.0', '7.1'], ruby: ['3.1', '3.3'], database: ['postgres'], paperclip: [false] } }
       - test_solidus:
           name: *name
           matrix: { parameters: { rails: ['7.0'], ruby: ['3.2'], database: ['sqlite'], paperclip: [false] } }