Update GB ref to point to official 1.16.0 tag

SergioEstevao · SergioEstevao · commit bac83b849150 · 2019-11-01T16:04:39.000Z
diff --git a/gutenberg b/gutenberg
@@ -1 +1 @@
-Subproject commit 76c9c4b1fbf3a90ad8d62245d811849ef65ec31e
+Subproject commit f6b72f2977a8c9ab3e2a958da904c765863b17f8
