Update activemodel requirement from >= 4.2, < 7.1.3 to >= 4.2, < 7.1.4

Updates the requirements on [activemodel](https://github.com/rails/rails) to permit the latest version.
- [Release notes](https://github.com/rails/rails/releases)
- [Changelog](https://github.com/rails/rails/blob/v7.1.3/activemodel/CHANGELOG.md)
- [Commits](rails/rails@v4.2.0...v7.0.8)

---
updated-dependencies:
- dependency-name: activemodel
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

freight_kit.gemspec

@@ -37,7 +37,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency('redcarpet', '~> 3.6.0') # for yard
   spec.add_development_dependency('yard', '~> 0.9.28')
 
-  spec.add_dependency('activemodel', '>= 4.2', '< 7.1.3')
+  spec.add_dependency('activemodel', '>= 4.2', '< 7.1.4')
   spec.add_dependency('activesupport', '>= 4.2', '< 7.1.4')
   spec.add_dependency('active_utils', '>= 3.3.1', '< 3.5.0')
   spec.add_dependency('httparty', '~> 0.10')