Update SKPs documentation link

Change-Id: I4bc1e4c331029d0939fa28910c6cbbc9697d666d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/541721
Reviewed-by: Herb Derby <herb@google.com>
diff --git a/bin/fetch-skps b/bin/fetch-skps
index ff9221f..e7cf72b 100755
--- a/bin/fetch-skps
+++ b/bin/fetch-skps
@@ -2,7 +2,7 @@
 
 # Copies the latest bot-generated SKP set to ./skps.
 # If you are having trouble, please refer to the instructions at:
-# https://sites.google.com/a/google.com/skia/key-resources/skps
+# go/download-skps
 
 set -x
 set -e