templates: bump max postgres connections to 10

By default, pgxpool.Pool has 4 connections (or number of cpus if higher).
Currently, we have 3 replicas, that means max 3*4=12 DB connections.

The dequeue operation is actually blocking - when a worker is waiting for
a job, one connection is blocked. My theory is that with 16 workers, we just
don't have enough connections that causes all sorts of weird slowdowns.

This commit bumps the number of connection from one replica to 10, therefore
we should be at 30 connections in total.

Signed-off-by: Ondřej Budai <ondrej@budai.cz>

test/cases/api.sh

@@ -79,6 +79,7 @@ pg_database = "osbuildcomposer"
 pg_user = "postgres"
 pg_password = "foobar"
 pg_ssl_mode = "disable"
+pg_max_conns = 10
 EOF
 
 sudo systemctl restart osbuild-composer