beets 1.4.9

This small update is part of our attempt to release new versions more often! There are a few important fixes, and we're clearing the deck for a change to beets' dependencies in the next version.

The new feature is:

• You can use the NO_COLOR environment variable to disable terminal colors. #3273

There are some fixes in this release:

• Fix a regression in the last release that made the image resizer fail to detect older versions of ImageMagick. #3269
• gmusic: The oauth_file config option now supports more flexible path values, including ~ for the home directory. #3270
• gmusic: Fix a crash when using version 12.0.0 or later of the gmusicapi module. #3270
• Fix an incompatibility with Python 3.8's AST changes. #3278

Here's a note for packagers:

• pathlib is now an optional test dependency on Python 3.4+, removing the need for a Debian patch. #3275