Updated client library documentation URLs. (#7307)

Previously, the URLs would redirect using JavaScript, which would either be slow or not work at all (in case JavaScript is disabled on the browser)

Author: pravindahal

README.rst

@@ -16,7 +16,7 @@ requests.
 .. |versions| image:: https://img.shields.io/pypi/pyversions/google-cloud-tasks.svg
    :target: https://pypi.org/project/google-cloud-tasks/
 .. _Cloud Tasks API: https://cloud.google.com/tasks
-.. _Client Library Documentation: https://googlecloudplatform.github.io/google-cloud-python/latest/tasks/index.html
+.. _Client Library Documentation: https://googleapis.github.io/google-cloud-python/latest/tasks/index.html
 .. _Product Documentation:  https://cloud.google.com/tasks
 
 Quick Start
@@ -32,7 +32,7 @@ In order to use this library, you first need to go through the following steps:
 .. _Select or create a Cloud Platform project.: https://console.cloud.google.com/project
 .. _Enable billing for your project.: https://cloud.google.com/billing/docs/how-to/modify-project#enable_billing_for_a_project
 .. _Enable the Cloud Tasks API.:  https://console.cloud.google.com/apis/library/cloudtasks.googleapis.com
-.. _Setup Authentication.: https://googlecloudplatform.github.io/google-cloud-python/latest/core/auth.html
+.. _Setup Authentication.: https://googleapis.github.io/google-cloud-python/latest/core/auth.html
 
 Installation
 ~~~~~~~~~~~~