Increase sock_pool_size and zmq_backlog values for Salt master

sock_pool_size: 1 -> 40
zmq_backlog: 1000 -> 3000

PROD-34114

Change-Id: I302e84e9662e6c26d630d9a2c1ad80085012902f
diff --git a/salt/master/single.yml b/salt/master/single.yml
index 64ddf88..76c4271 100644
--- a/salt/master/single.yml
+++ b/salt/master/single.yml
@@ -18,6 +18,8 @@
       command_timeout: 10
       opts:
         gather_job_timeout: 40
+        sock_pool_size: 40
+        zmq_backlog: 3000
       peer:
         '.*':
           - x509.sign_remote_certificate