gomod: update zoekt to include new libxml
Created by: keegancsmith
Our docker images include libxml2. Recently CVE-2022-23308 was released which affects it. By rebuilding our images we get the latest libxml2 which resolves the CVE. So as a side-effect of including the latest zoekt changes we will get docker images without the bad libxml2.
- acf74e5 indexserver: remove DownloadLimitMBPS
- e68ec97 bump ctags
Test Plan: CI. Both included commits are low risk to no risk.