audio/picard-plugins: Update to snapshot from 2019-03-12

• Add ALBUM_COLUMN option to enable the Add Album Column plugin - disabled by default since it changes the UI and the only way to disable it is to deinstall it. See: https://github.com/metabrainz/picard-plugins/pull/195
• Use BUILD_WRKSRC everywhere
• Remove hidden files and backup files from the build directory

New plugins (see: https://picard.musicbrainz.org/plugins/ for descriptions)

• Add Album Column
• Amazon cover art
• Apiseeds Lyrics
• Instruments
• TheAudioDB cover art