Update Getting Started example

Author: bjacquet

README.md

@@ -150,7 +150,7 @@ Using `Gemfile`
 
 ```ruby
 # latest stable
-gem 'ruby-saml', '~> 1.9.0'
+gem 'ruby-saml', '~> 1.11.0'
 
 # or track master for bleeding-edge
 gem 'ruby-saml', :github => 'onelogin/ruby-saml'