Use core minimum but allow 7.0/7.1/7.2 since core sets upper limit

This should be safe to use as is since the core application sets the rails version.
This will allow us to test with other versions on master.

Author: jrafanie

manageiq-ui-classic.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
   s.executables   = s.files.grep(%r{^exe/}) { |f| File.basename(f) }
   s.require_paths = ["lib"]
 
-  s.add_dependency "rails", ">= 6.0.4", "<7.1"
+  s.add_dependency "rails", ">= 7.0.8", "<8.0"
 
   s.add_dependency "execjs", "2.8.1" # Note: 2.8.1 requires uglifier 4.2.0 to defer uglifier asset compilation until asset compilation time: https://github.com/rails/execjs/issues/105
   s.add_dependency "high_voltage", "~> 3.0.0"