project.config: grant submit access to the 1.26 release branch

For go.dev/issue/76474.

Change-Id: I16037f45ff6f2e7a5dc7aa8c6e740ecafb513b48
Reviewed-on: https://go-review.googlesource.com/c/All-Projects/+/738540
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

project.config

diff --git a/project.config b/project.config
index 2bfa052..3985a12 100644
--- a/project.config
+++ b/project.config
@@ -170,6 +170,12 @@
 	viewAllAccounts = group luci_scoped_account
 	viewAllAccounts = group mdb/copybara-git-readers
 	viewAllAccounts = group mdb/gwsq
+[access "refs/heads/release-branch.go1.26"]
+	label-Auto-Submit = +0..+1 group cria/project-golang-approvers
+	label-Auto-Submit = +0..+1 group gobot
+	submit = group cria/project-golang-approvers
+	submit = group gobot
+	submit = group luci_scoped_account
 [notify "checkins"]
 	header = to
 	email = golang-checkins@googlegroups.com