Meshtastic Python 2.5.6 (hotfix)

This is a rerelease of 2.5.6 with some import errors fixed.

NOTE: to get back a few features, you may prefer to install with the pip spec of meshtastic[cli], which is now where color printing and QR code generation dependencies live.

What's Changed (since 2.5.5)

• Make several dependencies optional (dotmap, print_color, and pyqrcode) by @ianmcorvidae in #711

Full Changelog: 2.5.5...2.5.6post1