fix(transport): rename local max to avoid shadowing builtin

revive's redefines-builtin-id flags the local variable named max in
the LRU eviction loop, which shadows the Go 1.21 builtin. Rename it to
limit; no behavior change.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 4959e1f9-f8e6-4e97-a487-f395a0123c79

Author: joshfree

pkg/http/transport/etag.go

@@ -183,11 +183,11 @@ func (t *ETagTransport) add(key string, entry etagEntry) {
 	el := t.ll.PushFront(&lruItem{key: key, entry: entry})
 	t.items[key] = el
 
-	max := t.MaxEntries
-	if max <= 0 {
-		max = defaultETagCacheSize
+	limit := t.MaxEntries
+	if limit <= 0 {
+		limit = defaultETagCacheSize
 	}
-	for t.ll.Len() > max {
+	for t.ll.Len() > limit {
 		oldest := t.ll.Back()
 		if oldest == nil {
 			break