docs(gcp): update GCP permissions (#8350)

docs/tutorials/gcp/authentication.md

@@ -51,7 +51,7 @@ Prowler follows the same search order as [Google authentication libraries](https
 
 ???+ note
     The credentials must belong to a user or service account with the necessary permissions.
-    To ensure full access, assign the roles/viewer IAM role to the identity being used.
+    To ensure full access, assign the roles/reader IAM role to the identity being used.
 
 ???+ note
     Prowler will use the enabled Google Cloud APIs to get the information needed to perform the checks.
@@ -63,13 +63,12 @@ Prowler follows the same search order as [Google authentication libraries](https
 
 Prowler for Google Cloud needs the following permissions to be set:
 
-- **Viewer (`roles/viewer`) IAM role**: granted at the project / folder / org level in order to scan the target projects
+- **Reader (`roles/reader`) IAM role**: granted at the project / folder / org level in order to scan the target projects
 
 - **Project level settings**: you need to have at least one project with the below settings:
     - Identity and Access Management (IAM) API (`iam.googleapis.com`) enabled by either using the
     [Google Cloud API UI](https://console.cloud.google.com/apis/api/iam.googleapis.com/metrics) or
     by using the gcloud CLI `gcloud services enable iam.googleapis.com --project <your-project-id>` command
-    - Service Usage Consumer (`roles/serviceusage.serviceUsageConsumer`) IAM role
     - Set the quota project to be this project by either running `gcloud auth application-default set-quota-project <project-id>` or by setting an environment variable:
     `export GOOGLE_CLOUD_QUOTA_PROJECT=<project-id>`