Fix typo

Author: Ian Barber

README.md

@@ -14,7 +14,7 @@ http://developers.google.com/api-client-library/php
 
 ## Installation ##
 
-For the latest installation and setup instructions, see [the documentation[(https://developers.google.com/api-client-library/php/start/installation)
+For the latest installation and setup instructions, see [the documentation](https://developers.google.com/api-client-library/php/start/installation)
 
 ## Basic Example ##
 See the examples/ directory for examples of the key client features.