Fix the regular expression for the commit queue label access

Change-Id: Ic0690f1364090a11ea16679fac323e4070596bd9
Reviewed-on: https://go-review.googlesource.com/c/All-Projects/+/469995
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

project.config

diff --git a/project.config b/project.config
index c03fbd0..4740248 100644
--- a/project.config
+++ b/project.config
@@ -70,7 +70,7 @@
 	submit = group mdb/golang-release-eng-policy
 	label-Auto-Submit = +0..+1 group gobot
 	label-Auto-Submit = +0..+1 group mdb/golang-release-eng-policy
-[access "refs/heads/(master|release-branch.go1.20)"]
+[access "^refs/heads/(master|release-branch.go1.20)"]
 	label-Commit-Queue = +0..+2 group mdb/golang-release-eng-policy
 [label "Code-Review"]
 	function = NoBlock