Assign default add patch set permission on refs/for/*

By default each user should be able to add patch sets on all open changes.
We have created a new permission to lock changes, such that only
the change owner or a specific group can add new patchsets to exisitng
changes.

project.config

diff --git a/project.config b/project.config
index 1bc6688..3bd338d 100644
--- a/project.config
+++ b/project.config
@@ -28,11 +28,11 @@
 	label-Code-Review = -2..+2 group Project Owners
 	label-Code-Review = -2..+2 group mdb/boringssl-committers
 	label-Code-Review = -1..+1 group Registered Users
-	label-Commit-Queue = 0..+2 group External submitters
-	label-Commit-Queue = 0..+2 group Project Owners
-	label-Commit-Queue = 0..+2 group mdb/boringssl-committers
-	labelAs-Commit-Queue = 0..0 group commit-queue-bot
-        label-CQ-Verified = -1..1 group commit-queue-bot
+	label-Commit-Queue = +0..+2 group External submitters
+	label-Commit-Queue = +0..+2 group Project Owners
+	label-Commit-Queue = +0..+2 group mdb/boringssl-committers
+	labelAs-Commit-Queue = group commit-queue-bot
+        label-CQ-Verified = -1..+1 group commit-queue-bot
 	submit = group External submitters
 	submit = group Project Owners
 	submit = group commit-queue-bot
@@ -89,3 +89,5 @@
 
 [access "refs/heads/chromium-stable"]
 	push = +force group mdb/boringssl-committers
+[access "refs/for/*"]
+	addPatchSet = group Registered Users