We need to bundle bigdecimal, mutex_m, and drb on Ruby 3.4+

Author: amatsuda

test_projects/rails/rspec_rails/Gemfile

@@ -50,3 +50,7 @@ end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem "tzinfo-data", platforms: %i[mingw mswin x64_mingw jruby]
+
+gem "bigdecimal" if RUBY_VERSION >= '3.4'
+gem "mutex_m" if RUBY_VERSION >= '3.4'
+gem "drb" if RUBY_VERSION >= '3.4'