Update codereview.settings to set --squash as the default for git cl

Change-Id: I697143a111c4c13c9475b83c9174f2e0ed9de3e7
Reviewed-on: https://chromium-review.googlesource.com/325340
Reviewed-by: Mark Mentovai <mark@chromium.org>

codereview.settings

diff --git a/codereview.settings b/codereview.settings
index 6a368eb..2df1829 100644
--- a/codereview.settings
+++ b/codereview.settings
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 GERRIT_HOST: True
+GERRIT_SQUASH_UPLOADS: True
 CODE_REVIEW_SERVER: https://canary-chromium-review.googlesource.com/
 VIEW_VC: https://chromium.googlesource.com/chromium/mini_chromium/+/
 PROJECT: mini_chromium