The oauth2client library used in the google-calendar integration scripts has become deprecated. So, the script needs to be updated, to replace oauth2client with other libraries that Google is now using.

Refer to the quickstart example in the Google docs for what to use in the place of oauth2client.

Make sure that you update requirements.txt.

Set Up:
Refer to this integration doc for instructions to set up the integration. It's currently in the process of being updated as part of this PR, so until then you could refer to a screenshot of the updated version in that PR description.

Bonus tasks:
It would be nice to clean up the scripts as part of this.
And add a conventional example screenshot to the integration doc.

References:
For more on integrations, refer to these docs - Integrations Overview, and Non-webhook integrations.