update README

Author: davidgamez

functions-python/tasks_executor/src/tasks/validation_reports/README.md

@@ -19,4 +19,9 @@ Example:
     "filter_after_in_days": 14,
     "filter_statuses": ["active", "inactive", "future"]
 }
-`````
+`````
+
+# GCP environment variables
+The function uses the following environment variables:
+- `ENV`: The environment to use. It can be `dev`, `staging` or `prod`. Default is `dev`.
+- `LOCATION`: The location of the GCP project. Default is `northamerica-northeast1`.

functions-python/tasks_executor/src/tasks/validation_reports/rebuild_missing_validation_reports.py

@@ -141,7 +141,7 @@ def get_parameters(payload):
     Returns:
         dict: dict with: dry_run, filter_after_in_days, filter_statuses, prod_env, validator_endpoint parameters
     """
-    prod_env = os.getenv("ENVIRONMENT", "").lower() == "prod"
+    prod_env = os.getenv("ENV", "").lower() == "prod"
     validator_endpoint = get_gtfs_validator_url(prod_env)
     dry_run = payload.get("dry_run")
     filter_after_in_days = payload.get("filter_after_in_days")