Add command when specifying args for postgres (#1765)

When using args the container defaults to the entrypoint instead of command

causing postgres to be in a crashloop

roles/installer/templates/statefulsets/postgres.yaml.j2

@@ -56,6 +56,7 @@ spec:
             {{ postgres_security_context_settings | to_nice_yaml | indent(12) }}
 {% endif %}
 {% if postgres_extra_args %}
+          command: ["run-postgresql"]
           args: {{ postgres_extra_args }}
 {% endif %}
           env: