docs: update akscluster (#326)

Update tanzu-mission-control_akscluster.md

Changed AWS to AKS
Variable subscription should be subscription_id

Signed-off-by: Viktor van den Berg <viktorvdberg@yahoo.com>

Author: viktoriousss

docs/guides/tanzu-mission-control_akscluster.md

@@ -32,15 +32,15 @@ You can use the following template as reference to write your own `tanzu-mission
 
 // Read Tanzu Mission Control Azure AKS cluster : fetch cluster details
 data "tanzu-mission-control_akscluster" "tf_aks_cluster" {
-  credential_name = "<aws-credential-name>" // Required
-  subscription    = "<subscription>"        // Required
+  credential_name = "<aks-credential-name>" // Required
+  subscription_id = "<subscription_id>"        // Required
   resource_group  = "<resource-group>"      // Required
   name            = "<cluster-name>"        // Required
 }
 
 resource "tanzu-mission-control_akscluster" "tf_aks_cluster" {
   credential_name = "<credential-name>" // Required
-  subscription    = "<subscription>"    // Required
+  subscription_id = "<subscription_id>" // Required
   resource_group  = "<resource-group>"  // Required
   name            = "<cluster-name>"    // Required
 
@@ -197,4 +197,4 @@ resource "tanzu-mission-control_akscluster" "tf_aks_cluster" {
     }
   }
 }
-```
+```