[roll] Roll fuchsia [fx] Use dedicated config subdir

Populating this dir with a README also ensures the dir's existence
without every use case having to 'mkdir -p' it.

Original-Bug: 405468826
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1236185
Original-Revision: d3edc66c03638916b79a0bb4656f11436ba4cdcb
GitOrigin-RevId: 783dde6fbf7616a52ffe8ca0206b1b41839eb4c1
Change-Id: I8cd054b4737f15794d28d554e205763fd868579b

Author: David Fang

stem

@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="37d8e3077a7245704e07fc5dc83294bad6b88a75"/>
+             revision="d3edc66c03638916b79a0bb4656f11436ba4cdcb"/>
   </projects>
   <hooks>
     <hook name="install-environment"