update readme.md

Author: root

README.md

@@ -20,7 +20,7 @@ export BILLING_ID=""      ## e.g. 123456-ABCDEF-ZYXWVU
 export PROJECT_NAME=""    ## e.g. TerraHub
 export IAM_NAME=""        ## e.g. terraform
 export IAM_DESC=""        ## e.g. terraform service account
-export STORAGE_BUCKET="test"  ## e.g. terrahub_bucket_123456
+export STORAGE_BUCKET=""  ## e.g. terrahub_bucket_123456
 ```
 ### Setup BILLING_ID Programmatically