fix reference to contribsys values

README.md

@@ -18,7 +18,7 @@ Make sure that:
 * You have previously `ssh`-ed into all servers.
   * NOTE: If you are unsure about this, run `bin/sdr check_ssh -e [qa|stage|prod]` and watch the output for any errors!
 * NOTE: if you run `bin/sdr check_cocina`, you may need to ensure that you have the contribsys gem credentials available for google-books to install the sidekiq-pro gem locally (the credential is already on our deploy target VMs).
-  * You can get the env variable name and value from the README in shared_configs for google-books-prod (not in google-books-stage or -qa)
+  * The credentials are set via puppet from values stored in vault.
 * NOTE: You *may* invoke the `bin/` scripts via `bundle exec`.
 
 ### SSH Setup