Add new kokoro reader group.

In order to support Kokoro's migration to Pod, GoB reader permissions will now be granted through the ACL group kokoro-gob-readers(-qa) instead of directly to borg roles kokoro/kokoro-dedicated(-qa).

See go/kokoro-gob-permissions-update and b/266422763 for more details.

groups

diff --git a/groups b/groups
index 8e5cc94..77e4cdd 100644
--- a/groups
+++ b/groups
@@ -8,4 +8,5 @@
 mdb:aiyprojects-gerrit-owner            	mdb/aiyprojects-gerrit-owner
 mdb:kokoro                              	mdb/kokoro
 mdb:kokoro-dedicated                    	mdb/kokoro-dedicated
+mdb:kokoro-gob-readers                  	mdb/kokoro-gob-readers
 mdb:spacepark-kokoro                    	mdb/spacepark-kokoro

project.config

diff --git a/project.config b/project.config
index bfb88ed..5b030f4 100644
--- a/project.config
+++ b/project.config
@@ -15,6 +15,7 @@
 	read = group mdb/aiyprojects-gerrit-owner
 	read = group mdb/kokoro
 	read = group mdb/kokoro-dedicated
+	read = group mdb/kokoro-gob-readers
 	read = group mdb/spacepark-kokoro
 	revert = group Registered Users
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