Don't let index become out of date

[makew0rld]

Some fields like asset_origin_id are auto-indexed upon ingest by the webhook. These fields should be auto-indexed later on I think, for example if a CLI user updates the asset_origin_id but doesn't set --index. This is disobeying the user but is probably better than having an out-of-date index. Right?

Currently the auto-index list is small so this is not a big issue:

integrity-v2/webhook/attribute.go

Line 12 in 5d5cee1

var indexedStringKeys = []string{"file_name", "asset_origin_id", "project_id"}