Loosen Rails gem version requirements

One less thing to have to fix with Rails upgrades, and gem has not
needed changes for the past few upgrades anyway.

Author: rjpaskin

csv2db.gemspec

@@ -33,11 +33,11 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.add_dependency 'activerecord', '>= 4.2', '< 7.1'
-  spec.add_dependency 'activesupport', '>= 4.2', '< 7.1'
+  spec.add_dependency 'activerecord', '>= 4.2'
+  spec.add_dependency 'activesupport', '>= 4.2'
   spec.add_dependency 'charlock_holmes', '~> 0.7.3'
   spec.add_dependency 'dragonfly', '~> 1'
-  spec.add_dependency 'railties', '>= 4.2', '< 7.1'
+  spec.add_dependency 'railties', '>= 4.2'
   spec.add_dependency 'sidekiq', '>= 3'
 
   spec.add_development_dependency 'bundler', '>= 2.2.18', '< 3'