The v8.0 release contains backwards-incompatible changes.
Terraform >= 1.3.0 is required as cdn_policy and its nested attributes and objects are made optional in the backends object
The cdn_policy object attribute and its nested attributes within the [backends] variable (https://github.com/terraform-google-modules/terraform-google-lb-http/blob/0f0bf4cf0edceeee631c4a8e5d0140d40ca65128/variables.tf#L81) is optional now. If supplied, the value for for the CDN policy will be set as such. Since optional attributes
is a version 1.3 feature, the configuration will fail if the pinned version is < 1.3.