cmd/googlegolangorg: add google.golang.org/adk redirect

Internal tracking issue - b/435474163

Change-Id: I2507fed0fe099a23c4dc013dbd0597acf45f4d4b
Reviewed-on: https://go-review.googlesource.com/c/website/+/692135
Reviewed-by: Jaana Dogan <[email protected]>
Auto-Submit: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: Sam Thanawalla <[email protected]>
Reviewed-by: Hongxiang Jiang <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: hyangah

cmd/googlegolangorg/main.go

@@ -10,6 +10,10 @@ import (
 )
 
 var repoMap = map[string]Repo{
+	"adk": {
+		VCS: "git",
+		URL: "https://github.com/google/adk-go",
+	},
 	"api": {
 		VCS: "git",
 		URL: "https://github.com/googleapis/google-api-go-client",