refactor: set valid format for default s3 bucket name example
# AWS_ACCESS_KEY_ID=access_key_value
# AWS_SECRET_ACCESS_KEY=secret_access_key_value
# AWS_DEFAULT_REGION=us-east-2
-# AWS_S3_BUCKET_NAME=bucket_name
+# AWS_S3_BUCKET_NAME=bucket-name
#
# If using Google Cloud Storage as an object store:
# GCS_BUCKET_NAME=bucket_name
