Grant auto-submit rebase permission

Change-Id: Ib611938c6907c988c756ed0f5eb51187dd9f6bdb
Reviewed-on: https://pigweed-review.googlesource.com/c/Public-Commit-Queue-Projects/+/48240
Reviewed-by: Oliver Newman <olivernewman@google.com>

project.config

diff --git a/project.config b/project.config
index ab5cd80..d2c7631 100644
--- a/project.config
+++ b/project.config
@@ -23,6 +23,7 @@
 	label-Code-Review = +0..+2 group Pigweed Integration Roller
 	label-Code-Review = +0..+2 group Pigweed Roller
 	label-Pigweed-Auto-Submit = +0..+1 group Pigweed Source Committers
+	rebase = group Auto Submit
 [project]
 	description = Public projects using CQ.
 [label "Pigweed-Auto-Submit"]