This allows signing off commits with `git commit -s` Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes) Cleaned up DCO regex Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass) Upstream-commit: 4909a702045e621f236f5ec5470c8a9ec7fd7022 Component: engine