fix: update SimpleCov and Code Climate coverage configuration

- Replace JSONFormatter with built-in SimpleCov formatters
- Use MultiFormatter with SimpleFormatter and HTMLFormatter
- Simplify Code Climate reporter command format
- Remove redundant output path specification

.github/workflows/ruby.yml

@@ -118,7 +118,7 @@ jobs:
           chmod +x ./cc-test-reporter
           ./cc-test-reporter before-build
           bundle exec rspec
-          ./cc-test-reporter format-coverage --input-type simplecov --output coverage/codeclimate.json coverage/.resultset.json
+          ./cc-test-reporter format-coverage coverage/.resultset.json --input-type simplecov
           ./cc-test-reporter upload-coverage
 
       - uses: actions/[email protected]

spec/rails_helper.rb

@@ -7,9 +7,11 @@
   add_filter %r{^/db/}
   add_filter %r{^/vendor/}
 
-  # Specify the correct output format
-  coverage_dir 'coverage'
-  formatter SimpleCov::Formatter::JSONFormatter
+  # Use the default formatter instead of JSONFormatter
+  formatter SimpleCov::Formatter::MultiFormatter.new([
+    SimpleCov::Formatter::SimpleFormatter,
+    SimpleCov::Formatter::HTMLFormatter
+  ])
 end
 puts "required simplecov"