In the Authoring Guide, update the link to the canonical example

[jlara310]

In which file did you encounter the issue?

https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/AUTHORING_GUIDE.md

Did you change the file? If so, how?

No changes.

Describe the issue

The following link is broken:

The [Cloud Storage Sample](https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/storage/cloud-client/snippets.py)
is a great example of what we expect from samples.

Is there another canonical example you can recommend?

Thanks,
Juan