Document product factory default pubsub topic and Teams proxy function
Following https://gitlab.developers.cam.ac.uk/uis/devops/infra/gcp-product-factory/-/merge_requests/56 the product factory now creates a default "monitoring" related pubsub topic per-product, with an optional MS Teams proxy cloud function to forward specific alerts to a target Teams channel. This needs to be documented!
This is an example of how simple it is to include the pubsub notification channel in an alert policy in a product's infrastructure Terraform once the required product factory configuration is in place.