Update README.md

Author: ruudk

README.md

@@ -12,4 +12,4 @@ This package contains the following bundles which can be used to integrate
 - [DoctrineORMBridgeBundle](http://simplebus.github.io/SymfonyBridge/doc/doctrine_orm_bridge_bundle.html)
 
 Are you upgrading from a previous version? Read the [upgrade
-guide](http://simplebus.github.io/SymfonyBridge/doc/upgrade_guide.html).
+guide](http://simplebus.github.io/SymfonyBridge/doc/upgrade_guide.html).