fix 101-cosmos-db-autoscale example (#157)

quickstart/101-cosmos-db-autoscale/variables.tf

@@ -1,35 +1,42 @@
-variable "resource_group_name" {
+variable "prefix" {
   type        = string
-  description = "Resource group name"
+  default     = "cosmos-db-autoscale"
+  description = "Prefix of the resource name"
 }
 
 variable "location" {
   type        = string
+  default     = "eastus"
   description = "Resource group location"
 }
 
 variable "cosmosdb_account_name" {
   type        = string
+  default     = "default-cosmosdb-user"
   description = "Cosmos db account name"
 }
 
 variable "cosmosdb_account_location" {
   type        = string
+  default     = "eastus"
   description = "Cosmos db account location"
 }
 
 variable "cosmosdb_sqldb_name" {
   type        = string
+  default     = "default-cosmosdb-sqldb"
   description = "value"
 }
 
 variable "sql_container_name" {
   type        = string
+  default     = "default-sql-container"
   description = "SQL API container name."
 }
 
 variable "max_throughput" {
   type        = number
+  default     = 4000
   description = "Cosmos db database max throughput"
   validation {
     condition     = var.max_throughput >= 4000 && var.max_throughput <= 1000000