Upgrade Terraform version to the latest stable version

Terraform 1.3.5 (2 years ago) is the version we use to create the infrastructure. To upgrade terraform to the latest stable version 1.6.6 https://github.com/hashicorp/terraform/releases/tag/v1.6.0

The azurerm provider was updated from version 3.39.1 (1 year ago) to version 3.79.0 in MR_913 Terraform version upgrade is needed for compliancy.