Prevent caching of workflows

Summary: Fixes T9159.

Test Plan: Run arc patch on a code base requiring auth for a diff that has at least one dependency.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: avivey, thoughtpolice, joshuaspence, Korvin

Maniphest Tasks: T9159

Differential Revision: https://secure.phabricator.com/D14034