docs: fix link to docs on Chinese AWS site
The link at least went to an English page, but it was under
`docs.amazonaws.cn`.
@@ -100,7 +100,7 @@ example:
See `Using an IAM Role to Grant Permissions to Applications Running on
Amazon EC2
-Instances <https://docs.amazonaws.cn/en_us/IAM/latest/UserGuide/id_roles_use_switch-role-ec2.html>`__
+Instances <https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use_switch-role-ec2.html>`__
for details.
.. _aws-network-requirements:
