feat: edit readme and variables

gcp/terraform/operations/budget-alert/README.md

@@ -14,4 +14,7 @@ on the Project level:
 
 ## Notes:
 - Create and upload your backend.tf in input section of the building block definition in meshStack
-- add your service account JSON key containings as a string and encrypted environment variable and name it "GOOGLE_CREDENTIALS"
+- Add your service account JSON key containings as a string and encrypted environment variable and name it "GOOGLE_CREDENTIALS".
+  **Note**: If you have your provider and backend configuration already generated from collie-hub, uploading those files along with the key.json file as inputs will suffice.
+  - Capture the value of your billing account ID from the GCP portal > Billing section.
+

gcp/terraform/operations/budget-alert/variables.tf

@@ -13,7 +13,7 @@ variable "budget_amount" {
   description = "The amount of monthly Budget specified for this project"
 }
 
-variable "alert_treshold" {
+variable "alert_threshold" {
   type        = string
   description = "Ratio of the budget amount that you want to receive an alert when it reached. e.g. '0.5' means 50%"
 }