gomod: update zoekt

Created by: keegancsmith

We haven't updated zoekt in a while.

• https://github.com/sourcegraph/zoekt/commit/65ca553 indexserver: compound shard support
• https://github.com/sourcegraph/zoekt/commit/a585b18 indexserver: only show logs in test if verbose
• https://github.com/sourcegraph/zoekt/commit/769a9fc merge: return compound filename from Merge
• https://github.com/sourcegraph/zoekt/commit/e2c9792 update base Dockerfile
• https://github.com/sourcegraph/zoekt/commit/1a4a28c update all packages each build to avoid CVEs
• https://github.com/sourcegraph/zoekt/commit/62b7b9a Make repo config batch size configurable
• https://github.com/sourcegraph/zoekt/commit/fbbfd2e build: don't count content of skipped files
• https://github.com/sourcegraph/zoekt/commit/89fbe6e indexserver: SIGUSR1 triggers updates
• https://github.com/sourcegraph/zoekt/commit/a3bd8ee indexserver: remove codehost label from metrics