go.mod: bump zoekt

Created by: stefanhengl

• 8e025c4 debug: remove "debug find"
• 4a774cf explode: delete input shard first
• 7bfb736 zoekt-mirror-gerrit: fix typo
• 300e175 zoekt-mirror: allow to index only active projects
• 7dc4539 zoekt-mirror-gerrit: fix issue when anonymous http is disabled on Gerrit
• 321d522 builder: implement basic delta shard functioanlity
• f150b3a ctags: only include log output for debug
• 781cfea merging: tolerate process interruptions during merging
• 881cec1 indexserver: add debug subcommand
• 27375b3 indexserver: remove deprecated GetIndexOptions
• 1210f0f webserver: remove kubernetes sd drain time
• b5c8272 indexserver: remove atomics for fingerprint
• 0316d52 shardedSearcher - implement functionality for filetombstones
• 8082708 all: switch to RFC3339 for timestamps in log files
• 9d43e8e merging: add unit test for explode
• 39b2af4 merging: support exploding compound shards

Test plan

This is already rolled out to production. This PR just aligns the repo with deploy-sourcegraph-cloud.