fix: update kafka_protocol from 4.0.1 to 4.0.3

Prior to this change the actual time spent in establishing a
Kafka connection might be longer than desired due to the timeout
being used in SSL upgrade (if enabled), then API version query.

This has been fixed by turning the given timeout config
into a deadline, and the sub-steps will try to meet the deadline.
see more details here:
kafka4beam/kafka_protocol#92

rebar.config

@@ -1,5 +1,5 @@
 {deps, [ {supervisor3, "1.1.11"}
-       , {kafka_protocol, "4.0.1"}
+       , {kafka_protocol, "4.0.3"}
        , {snappyer, "1.2.8"}
        ]}.
 {edoc_opts, [{preprocess, true}, {macros, [{build_brod_cli, true}]}]}.