Allow trusted contributors to verify java-prettify changes

java-prettify and other public projects currently only allow project
owners to vote Verified+1. Allow others with Verified+1 permission
on gerrit to vote Verified+1 here, too, to smooth the contribution
process if they've done testing in a repository without zuul set up.

Change-Id: I0870e3f4dbf9fb4e16287470510469037f65a7ed

project.config

diff --git a/project.config b/project.config
index 94dbe38..b50865f 100644
--- a/project.config
+++ b/project.config
@@ -21,6 +21,7 @@
 	label-Code-Review = -1..+1 group Registered Users
 	label-Verified = -1..+1 group Diffy Cuckoo
 	label-Verified = -1..+1 group Project Owners
+	label-Verified = -1..+1 group gerrit-trusted-contributors
 	submit = group Project Owners
 	editTopicName = +force group Project Owners
 	editTopicName = +force group gerrit-trusted-contributors