docs: fix link to github hosted reference docs (#2598)

Author: adriankirchner

README.md

@@ -7,7 +7,7 @@ list of [Google cloud packages](https://cloud.google.com/php/docs/reference) fir
 these are the recommended libraries.
 
 <dl>
-  <dt>Reference Docs</dt><dd><a href="https://googleapis.giPHthub.io/google-api-php-client/main/">https://googleapis.github.io/google-api-php-client/main/</a></dd>
+  <dt>Reference Docs</dt><dd><a href="https://googleapis.github.io/google-api-php-client/main/">https://googleapis.github.io/google-api-php-client/main/</a></dd>
   <dt>License</dt><dd>Apache 2.0</dd>
 </dl>