Remove unused net_profile_docker_bridge_cidr

Since 2020 the default runtime is containerd and not Docker
https://github.com/Azure/AKS/blob/master/CHANGELOG.md#release-2020-06-29

The setting docker_bridge_cidr is doing nothing.
If you check the interfaces on the AKS nodes they dont have any Docker bridge configured.

README.md

@@ -74,7 +74,6 @@ module "aks" {
 
   network_policy                 = "azure"
   net_profile_dns_service_ip     = "10.0.0.10"
-  net_profile_docker_bridge_cidr = "170.10.0.1/16"
   net_profile_service_cidr       = "10.0.0.0/16"
 
   depends_on = [module.network]
@@ -352,4 +351,4 @@ No modules.
 | <a name="output_password"></a> [password](#output\_password)                                                                                        | n/a                                                                                                    |
 | <a name="output_system_assigned_identity"></a> [system\_assigned\_identity](#output\_system\_assigned\_identity)                                    | n/a                                                                                                    |
 | <a name="output_username"></a> [username](#output\_username)                                                                                        | n/a                                                                                                    |
-<!-- END_TF_DOCS -->
+<!-- END_TF_DOCS -->