message: Adds warning about env vars.
diff: @@ -6,6 +6,8 @@ jobs:
  xcode: "10.1.0"
  environment:
  + # WARNING: These env vars are passed to PRs on forks.
  + # WARNING: DO NOT PUT SENSITIVE INFORMATION HERE.
  ArtsyAPIClientSecret: "-"
  ArtsyAPIClientKey: "-"
  StripePublishableKey: "-"
  