Update rspec-rails

Author: jcoyne

openseadragon.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "engine_cart"
-  spec.add_development_dependency "rspec-rails", '~> 3.1'
+  spec.add_development_dependency "rspec-rails", '~> 6.1'
   spec.add_development_dependency "capybara"
   spec.add_development_dependency "sqlite3"