slowlog get - does not include fields added in Redis version 4

[RoeyPrat]

Version: What redis-py and what redis version is the issue happening on?
any version of redis-py up to master (last release Is 3.5.3), and Redis version 4+
Platform: What platform / version? (For example Python 3.5.1 on Windows 7 / Ubuntu 15.10 / Azure)
issue is platform agnostic.
Description: Description of your issue, stack traces from errors and code that reproduces the issue
slowlog get does not include fields added in Redis version 4:

• Client IP address and port (4.0 only).
• Client name if set via the CLIENT SETNAME command (4.0 only).

[RoeyPrat]

noticed in PR #1352

[RoeyPrat]

@ian28223 let me know if you want to work on this issue. If not, I'll handle it.

[ian28223]

@RoeyPrat feel free to work on it and close mine. please link me to the new PR though so I can watch it. Thanks!