[roll] Roll fuchsia [fx][gerrit-submit] Improve error message on auth failure.

When authentication fails, the HTTP response from the server contains
instructions about how to generate a new password, but this is hard
to read (as it is embedded in HTML and headers).

Update our own error message to explain how to generate a password
more clearly.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/578504
Original-Revision: a6d7c7dc2d61903120e462a4ba9fcceede9914ed
GitOrigin-RevId: 51fb36ddb9089cfa486305558a42d61a258625bc
Change-Id: Ie951b9312868341fd72169dd4c04f45125e4e883
diff --git a/stem b/stem
index 1a07e8c..7202064 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="6f0276e58445f5d8e29d728e8ea317e6a6762b79"/>
+             revision="a6d7c7dc2d61903120e462a4ba9fcceede9914ed"/>
   </projects>
   <hooks>
     <hook name="install-environment"