gomod: update zoekt
Created by: keegancsmith
- https://github.com/sourcegraph/zoekt/commit/b86ecca rpc: cache encoding of queries
- https://github.com/sourcegraph/zoekt/commit/7b4309d ctags: update expected output in TestJSON
- https://github.com/sourcegraph/zoekt/commit/907d491 dev: set fork, public, archived based on sentinel files
- https://github.com/sourcegraph/zoekt/commit/bee74c2 toc: modify disk format to include names for backwards/forwards compatiblity.