challenge: lower preload-early-hint-deadline to 2 seconds by default

examples/snippets/challenges-non-js.yml

@@ -9,7 +9,7 @@ challenges:
     condition: '"Sec-Fetch-Mode" in headers && headers["Sec-Fetch-Mode"] == "navigate"'
     runtime: "preload-link"
     parameters:
-      preload-early-hint-deadline: 3s
+      preload-early-hint-deadline: 2s
 
   # Challenges with a redirect via Refresh header (non-JS, requires HTTP parsing and logic)
   header-refresh:

lib/challenge/preload-link/preload-link.go

@@ -22,7 +22,7 @@ type Parameters struct {
 }
 
 var DefaultParameters = Parameters{
-	Deadline: time.Second * 3,
+	Deadline: time.Second * 2,
 }
 
 func FillRegistration(state challenge.StateInterface, reg *challenge.Registration, parameters ast.Node) error {