Remove 'six' from roll_chromium_deps. This dep was causing the script to fail. It may be because the repo currently has a single commit. Work around this by removing the entry from the auto-roller for now. Bug: angleproject:2344 Change-Id: Id4f61124aae7ab43aa2343faf19416ff676314d7 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2842224 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>