Do not raise exception when decoding packets

[wojtekmach]

It crashes the connection:

iex(1)> {:ok, pid} = MyXQL.start_link([]); MyXQL.query!(pid, "SELECT TIME(ADDTIME('23:00:00', '02:00:00'))")
** (ArgumentError) cannot decode "1d 01:00:00" as time, negative or >= 24:00:00 values are not supported
    (myxql 0.4.2) lib/myxql/protocol/values.ex:511: MyXQL.Protocol.Values.time/6
    (myxql 0.4.2) lib/myxql/protocol/values.ex:481: MyXQL.Protocol.Values.decode_time/4
    (myxql 0.4.2) lib/myxql/protocol.ex:539: MyXQL.Protocol.decode_resultset/4
    (myxql 0.4.2) lib/myxql/client.ex:197: MyXQL.Client.recv_packets/6
    (myxql 0.4.2) lib/myxql/connection.ex:102: MyXQL.Connection.handle_execute/4
    (db_connection 2.2.1) lib/db_connection/holder.ex:316: DBConnection.Holder.holder_apply/4
    (db_connection 2.2.1) lib/db_connection.ex:1255: DBConnection.run_execute/5
    (db_connection 2.2.1) lib/db_connection.ex:1342: DBConnection.run/6
    (db_connection 2.2.1) lib/db_connection.ex:539: DBConnection.parsed_prepare_execute/5
    (db_connection 2.2.1) lib/db_connection.ex:532: DBConnection.prepare_execute/4
    (myxql 0.4.2) lib/myxql.ex:235: MyXQL.do_query/4
    (myxql 0.4.2) lib/myxql.ex:258: MyXQL.query!/4
iex(1)>
19:47:44.063 [error] GenServer #PID<0.217.0> terminating
** (DBConnection.ConnectionError) client #PID<0.213.0> stopped: ** (ArgumentError) cannot decode "1d 01:00:00" as time, negative or >= 24:00:00 values are not supported

Instead we should return an error tuple and later decide what to do with it.

We may still want to disconnect because if we stop decoding in the middle, there might be still data on the socket which may or may not be a problem.

[wojtekmach]

This also makes CI occasionally fail: https://github.com/elixir-ecto/myxql/runs/1359973771?check_suite_focus=true