Merge pull request #166 from intercom/as/readme_markdown_fix

Markdown syntax fix

Author: Andy Scott

README.md

@@ -41,7 +41,7 @@ $client = new IntercomClient(appId, apiKey);
 
 Or if using an OAuth or Personal Access Token use:
 
-``php
+```php
 use Intercom\IntercomClient;
 
 $client = new IntercomClient(<insert_token_here>, null);