Add Ruby 3.3, Drop Ruby < 3.0 and Rails < 6.1 (#41)

* drop obsoleted rails and ruby versions

- drop rails < 6.1
- drop ruby < 3.0

* add ruby 3.3 in CI

* fix deprecation warning

```
DEPRECATION WARNING: Support for
`config.active_support.cache_format_version = 6.1` has been deprecated
and will be removed in Rails 7.2.
```

* fix deprecation warning

`fixture_path=` has deprecated

ref: https://edgeguides.rubyonrails.org/7_1_release_notes.html#active-record-deprecations

* fix load_defaults version number for RAILS_VERSION=master

.github/workflows/ci.yml

@@ -11,22 +11,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rails_version: [5.1.0, 5.2.0, 6.0.0, 6.1.0, 7.0.0, 7.1.0, master]
-        ruby_version: ['3.2', '3.1', '3.0', '2.7', '2.6']
-        exclude:
-          - { ruby_version: '2.6', rails_version: 7.0.0 }
-          - { ruby_version: '2.6', rails_version: 7.1.0 }
-          - { ruby_version: '2.6', rails_version: master }
-          - { ruby_version: '3.0', rails_version: 5.1.0 }
-          - { ruby_version: '3.0', rails_version: 5.2.0 }
-          - { ruby_version: '3.1', rails_version: 5.1.0 }
-          - { ruby_version: '3.1', rails_version: 5.2.0 }
-          - { ruby_version: '3.1', rails_version: 6.0.0 }
-          - { ruby_version: '3.1', rails_version: 6.1.0 }
-          - { ruby_version: '3.2', rails_version: 5.1.0 }
-          - { ruby_version: '3.2', rails_version: 5.2.0 }
-          - { ruby_version: '3.2', rails_version: 6.0.0 }
-          - { ruby_version: '3.2', rails_version: 6.1.0 }
+        rails_version: [6.1.0, 7.0.0, 7.1.0, master]
+        ruby_version: ['3.3', '3.2', '3.1', '3.0']
 
     steps:
     - uses: actions/checkout@v3

spec/dummy/config/application.rb

@@ -7,6 +7,7 @@
 
 module Dummy
   class Application < Rails::Application
+    config.load_defaults Rails.version.to_f
     config.secret_token = "secret token"
     config.active_support.deprecation = :log
     config.eager_load = false

spec/rails_helper.rb

@@ -45,7 +45,12 @@
 end
 RSpec.configure do |config|
   # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
-  config.fixture_path = File.expand_path('fixtures', __dir__)
+  fixture_path = File.expand_path('fixtures', __dir__)
+  if config.respond_to?(:fixture_paths=) # NOTE: check for Rails 6.1
+    config.fixture_paths = [fixture_path]
+  else
+    config.fixture_path = fixture_path
+  end
 
   # If you're not using ActiveRecord, or you'd prefer not to run each of your
   # examples within a transaction, remove the following line or assign false