DirIndex etag is based on xxhash(./assets/dir-index-html), so we need to fetch it dynamically

Implementation	bifrost-gateway	boxo	kubo
Conformance Version	main	main	main
Total	✅2	✅2	✅2
Header Etag	✅1	✅1	✅1
Status code	✅1	✅1	✅1