docs: make ref docs more visible (#305)

README.md

@@ -2,6 +2,7 @@
 
 <dl>
   <dt>Homepage</dt><dd><a href="http://www.github.com/google/google-auth-library-php">http://www.github.com/google/google-auth-library-php</a></dd>
+  <dt>Reference Docs</dt><dd><a href="https://googleapis.github.io/google-auth-library-php/master/">https://googleapis.github.io/google-auth-library-php/master/</a></dd>
   <dt>Authors</dt>
     <dd><a href="mailto:[email protected]">Tim Emiola</a></dd>
     <dd><a href="mailto:[email protected]">Stanley Cheung</a></dd>
@@ -15,8 +16,6 @@
 This is Google's officially supported PHP client library for using OAuth 2.0
 authorization and authentication with Google APIs.
 
-View the [reference documentation][ref-docs].
-
 ### Installing via Composer
 
 The recommended way to install the google auth library is through
@@ -219,7 +218,6 @@ hesitate to
 [ask questions](http://stackoverflow.com/questions/tagged/google-auth-library-php)
 about the client or APIs on [StackOverflow](http://stackoverflow.com).
 
-[ref-docs]: https://googleapis.github.io/google-auth-library-php/master/
 [google-apis-php-client]: https://github.com/google/google-api-php-client
 [application default credentials]: https://developers.google.com/accounts/docs/application-default-credentials
 [contributing]: https://github.com/google/google-auth-library-php/tree/master/.github/CONTRIBUTING.md