Missing resource needed to build AKS with ACR

[JimPaine]

Bicep version
Bicep CLI version 0.3.1 (d0f5c9b)

Describe the bug
The VSCode extension shows that the resource type "Microsoft.ContainerRegistry/registries/providers/roleAssignments@2017-09-01" is not available and the compiler gives a warning " Warning BCP081: Resource type "Microsoft.ContainerRegistry/registries/providers/roleAssignments@2017-09-01" does not have types available."

To Reproduce
Build an AKS cluster with ACR and add a role assignment to allow ACRPull

...
resource acrrole 'Microsoft.ContainerRegistry/registries/providers/roleAssignments@2017-09-01' = {
  name: '${acr.name}/Microsoft.Authorization/${guid(acr.id, 'AcrPull')}'
  properties: {
    roleDefinitionId: subscriptionResourceId('Microsoft.Authorization/roleDefinitions', '7f951dda-4ed3-4680-a7ca-43fe172d538d')
    principalId: reference(aks.id).identityProfile.kubeletidentity.objectId
    principalType: 'ServicePrincipal'
  }
}
...

Additional context
While the above works if you ignore the errors, not having the type available in the extension or compiler makes it hard to consume and build out a valid environment

[JimPaine]

Covered by #870