run: be more explicit with rev-list

When building out-of-source, Git is complaining that the refs are
ambiguous as paths. The `--` forces Git to recognize them as refs.
Status Job ID Name Coverage
  External
passed kwrobot-branch-check

passed rust-git-hooks-megas-linux-debug

passed rust-git-hooks-megas-linux-debug

passed rust-git-hooks-megas-linux-debug

passed rust-git-hooks-megas-linux-debug

passed rust-git-hooks-megas-linux-debug

00:00:04