Connecting to server URL without port results in CLI error

[mikebin]

Describe the bug
Connecting to a server URL without a port number (defaulting to 80 or 443) results in an error: Server URL must begin with protocol (e.g., http:// or https://) in ksqlDB 6.0.0.

To Reproduce
Steps to reproduce the behavior, include:
Version: 6.0.0 (CLI and Server)

ksql http://localhost

                  ===========================================
                  =       _              _ ____  ____       =
                  =      | | _____  __ _| |  _ \| __ )      =
                  =      | |/ / __|/ _` | | | | |  _ \      =
                  =      |   <\__ \ (_| | | |_| | |_) |     =
                  =      |_|\_\___/\__, |_|____/|____/      =
                  =                   |_|                   =
                  =  Event Streaming Database purpose-built =
                  =        for stream processing apps       =
                  ===========================================

Copyright 2017-2020 Confluent Inc.

CLI v6.0.0, Server v<unknown> located at http://localhost

Having trouble? Type 'help' (case-insensitive) for a rundown of how things work!

Server URL must begin with protocol (e.g., http:// or https://)
ksql> show topics;
port p must be in range 0 <= p <= 65535

Expected behavior
Successful connection using standard implicit port (80 or 443).

Actual behaviour
See above.

Additional context
Workaround is to add the implicit port number to the URL:

ksql http://localhost:80

This issue does not occur in earlier CLI versions.

[AlanConfluent]

Is this a regression?

[mikebin]

Seems to be, port number is not required in CLI 5.5.1