gopls: add the link to the gopls/README.md

Change-Id: I6113ca988afa7a9d1dc0a865c6981400ac242c9d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/217082
Reviewed-by: Ian Cottrell <iancottrell@google.com>
diff --git a/gopls/main.go b/gopls/main.go
index 0b4d889..0de6531 100644
--- a/gopls/main.go
+++ b/gopls/main.go
@@ -6,6 +6,9 @@
 // The Language Server Protocol allows any text editor
 // to be extended with IDE-like features;
 // see https://langserver.org/ for details.
+//
+// See https://github.com/golang/tools/tree/master/gopls
+// for the most up-to-date information on the gopls status.
 package main // import "golang.org/x/tools/gopls"
 
 import (