Update azuread provider version to 2.7.0
Update azuread provider version to 2.7.0

Version 2.0.0 fails to create azure group, with this error:

```azuread_group.aks_cluster_admins: Creating...
╷
│ Error: Could not retrieve owner principal object "a0630******"
│ 
│   with azuread_group.aks_cluster_admins,
│   on azuread.tf line 12, in resource "azuread_group" "aks_cluster_admins":
│   12: resource "azuread_group" "aks_cluster_admins" {
│ 
│ ODataId was nil
```
Upgrade to 2.7.0 fixed it.
hashicorp/terraform-provider-azuread,hashicorp/terraform-provider-azuread,hashicorp/terraform-provider-azuread