project.config: add mdb/google-cla-gerrit-robot-accounts group for SignCLA

Add the mdb/google-cla-gerrit-robot-accounts group, and consider it
to have accepted the "Google CLA" contributor agreement. This change
implements the new Gerrit process for allowlisting bots to bypass
CLA checks via an mdb group, as documented at go/gob/team/signcla.

We don't have bots that make use of this ability yet, but it is safe
to add preemptively, making it possible to start using the mdb group
for future bots or to convert existing ones. It brings Go project's
configuration closer to what can be considered as the default.

Updates go.dev/issue/38075.
Updates b/198293761.

Change-Id: I53792f6786156349fa746441b1b41de7f5e18811

groups

diff --git a/groups b/groups
index 6b6e2ef..242c815 100644
--- a/groups
+++ b/groups
@@ -18,3 +18,4 @@
 mdb:gerritcodereview-eng                                      	mdb/gerritcodereview-eng
 mdb:golang-gob-eng-policy                                     	mdb/golang-gob-eng-policy
 mdb:golang-gob-owners                                         	mdb/golang-gob-owners
+mdb:google-cla-gerrit-robot-accounts                          	mdb/google-cla-gerrit-robot-accounts

project.config

diff --git a/project.config b/project.config
index f711f8a..f466f6d 100644
--- a/project.config
+++ b/project.config
@@ -115,6 +115,7 @@
 	accepted = group google/google-union:signcla
 	accepted = group ldap/employees
 	accepted = group ldap/interns
+	accepted = group mdb/google-cla-gerrit-robot-accounts
 [capability]
 	administrateServer = group mdb/golang-gob-owners
 	gerrit-google-manageUsersGet = group gobot