How can I send the alerts to Google hangout?

Sumo Logic does not provide the webhook template for the google hangout, but you can create a generic webhook connection in Sumo Logic for the same. Please see here to know how to setup webhook connections

You need to follow the steps in the below article from google to generate a Google Hangout webhook URL, which you can then use within Sumo Logic's generic webhook. You will need to check acceptable JSON payload from google hangout from the below link and you can use the same payload while creating generic webhook connection.

https://developers.google.com/hangouts/chat/how-tos/webhooks