client: remove cache TODO

Don't cache entry lookups by ID.

Although it would be easy enough to use Cache.{Read,Write}Entries to
store a single entry under its ID, detecting stale entries would add
complexity. The index is used for module staleness, but there is no
similar place to store last-modified times for individual entries.

Until we know that users will repeatedly request entries by ID, it's
not worth the effort to cache them.

Change-Id: I74b8b7fff50e99fa8670c1c3b63018be44638675
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/357036
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/client/client.go b/client/client.go
index 6666d71..74916b1 100644
--- a/client/client.go
+++ b/client/client.go
@@ -224,7 +224,6 @@
 }
 
 func (hs *httpSource) GetByID(id string) (*osv.Entry, error) {
-	// TODO(jba): cache?
 	content, err := hs.readBody(fmt.Sprintf("%s/%s/%s.json", hs.url, internal.IDDirectory, id))
 	if err != nil || content == nil {
 		return nil, err