Fix changelog to follow the same format that has been used for
some time now

* Bugfixes:
- PICARD-1991 - Case-only changes to file names are not applied
on case insensitive file systems on Linux
- PICARD-1992 - Case-only changes to file names are not applied
on FAT32 and exFAT file systems on Windows 10
- PICARD-2001 - Directory drag & drop from file browser to
cluster area broken
- PICARD-2004 - Metadata changes loaded asynchronously by
plugins are reset if file gets matched to track
- PICARD-2005 - Modified fields are sometimes not correctly
marked as changed when multiple files are selected
- PICARD-2006 - "Local files" cover provider does not detect
cover files for files already present at release loading time
- PICARD-2012 - Loaded files not shown in UI if release
MBID is a redirect
- PICARD-2014 - Config upgrade from Picard < 1.3.0 to
version 2.4 or later fails
* Improvements:
- PICARD-1828 - Allow assigning cover art to multiple selected
files
- PICARD-1999 - Provide binary distributions for Windows and
macOS on PyPI
- PICARD-2007 - Disable analyze / audio fingerprinting for MIDI
files
* Bugfixes:
- PICARD-1987 - Special variables %_multiartist%, %_pregap%,
%_datatrack% and %_totalalbumtracks% missing after files
got matched to a track
- PICARD-1988 - Aborts if directory scan finds a directory
which cannot be read