Update README.md

Author: drew-hirewheel

README.md

@@ -22,8 +22,6 @@ Uncompress the zip file you download, and include the autoloader in your project
 require_once '/path/to/datarole-api-php-client/vendor/autoload.php';
 ```
 
-For additional installation and setup instructions, see [the documentation](https://github.com/datarole/api/blob/master/sdks/php.md#installation).
-
 ## Basic Example ##
 Begin by editing the examples/index.php file and replacing the placeholder text with your provided account and secret keys.  If you want to test a specific address, just replace the default address in the lookupAddress() function.