Fix 101-synapse (#187)

* fix 101-synapse

Co-authored-by: zjhe <hezijie@microsoft.com>

quickstart/101-synapse/locals.tf

@@ -1,4 +1,8 @@
+resource "random_pet" "name" {
+  count = var.name == null ? 1 : 0
+}
+
 locals {
-  basename      = "${var.name}-${var.environment}"
+  basename      = "${try(random_pet.name[0].id, var.name)}-${var.environment}"
   safe_basename = replace(local.basename, "-", "")
 }