The tj-actions/changed-files repo has been taken down to the security
incident
(https://www.stepsecurity.io/blog/harden-runner-detection-tj-actions-changed-files-action-is-compromised).
This patch moves these jobs over step-security's fork, which has been
loosely audited and has had the malicious commits removed. This is
mainly intended as a stop-gap to get these actions running again while
we figure out the best path forward.
6616acd80c