bump zoekt
Created by: tsenart
- https://github.com/sourcegraph/zoekt/commit/078fa3e stats: add new stats to stats line (#166)
- https://github.com/sourcegraph/zoekt/commit/6c893ff all: use BranchesRepos instead of RepoSet in tests (#165)
- https://github.com/sourcegraph/zoekt/commit/20c04be indexserver: fix wrong type in log format