Update rails requirement from = 7.0.8 to = 7.1.2

Updates the requirements on [rails](https://github.com/rails/rails) to permit the latest version.
- [Release notes](https://github.com/rails/rails/releases)
- [Commits](rails/rails@v7.0.8...v7.1.2)

---
updated-dependencies:
- dependency-name: rails
  dependency-type: direct:development
...

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

mail-notify.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "coveralls", "~> 0.8.22"
   spec.add_development_dependency "pry", "~> 0.14.1"
-  spec.add_development_dependency "rails", "7.0.8"
+  spec.add_development_dependency "rails", "7.1.2"
   spec.add_development_dependency "rake", "~> 13.0.6"
   spec.add_development_dependency "rspec-rails", "~> 5.1"
   spec.add_development_dependency "standard", "~> 1"