py-sounddevice: update to 0.4.6, update python versions

[contextnerror]

Description

Type(s)

• [ ] bugfix
• [ ] enhancement
• [ ] security fix

Tested on

macOS 10.14.6 18G9323 x86_64 Command Line Tools 10.3.0.0.1.1562985497

Verification

Have you

• [x] followed our Commit Message Guidelines?
• [x] squashed and minimized your commits?
• [x] checked that there aren't other open pull requests for the same change?
• [x] checked your Portfile with port lint --nitpick?
• [ ] tried a full install with sudo port -vst install?
• [ ] tested basic functionality of all binary files?

[macportsbot]

Notifying maintainers: @mojca for port py-sounddevice.