Update gcp.md (#22)

Author: dylanTruffle

content/docs/tutorials/gcp.md

@@ -44,6 +44,8 @@ Replace the leaked GCP API Key with the new one in all impacted applications and
 ---
 ## Revoke the Leaked GCP API Key
 
+#### *Note: deleting the project that contains the key, does not ensure swift deactivation of that key. GCP services and traffic can remain active up to 30 days after scheduling a project for deletion*
+
 ### Step 1 - Navigate to the relevant Service Account page
 #### 1a. Navigate to the impacted GCP project
 #### 1b. Click on the `IAM & Admin` tab
@@ -75,4 +77,4 @@ A message will pop up informing you that the key has been deleted.
 
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 ## Resources
-- [GCP API Key Documentation](https://cloud.google.com/docs/authentication/api-keys#introduction)
+- [GCP API Key Documentation](https://cloud.google.com/docs/authentication/api-keys#introduction)