docs: update link to python library

RE: #702

Author: stephenplusplus

docs/site/components/language-switcher/language-switcher.html

@@ -80,7 +80,7 @@ <h4 class="list-item--heading">gcloud Libraries</h4>
       </a>
     </li>
     <li>
-      <a href="https://googlecloudplatform.github.io/gcloud-python" title="gcloud-python Documentation" class="skip-external-link">
+      <a href="https://googlecloudplatform.github.io/gcloud-python/latest" title="gcloud-python Documentation" class="skip-external-link">
         <img src="site/img/icon-lang-python.svg" alt="gcloud-python" class="menu-icon">
         Python
       </a>