Log Message:
Update to 1.8.0. From the changelog:

- `mob next` does not show the same committer multiple times in the list
  of previous committers.
- `mob next` does not suggest the current Git user to be the next typist
  as long as there were other persons involved in the mob.
- `mob next` performs a simple lookahead to also suggest persons who
  might have been absent only during the last mob round.
- When user.name is not set in the git config, mob no longer shows an
  error but a warning with a help how to fix it.