Update vendored beets to 1.6.0

Updates colorama to 0.4.6
Adds confuse version 1.7.0
Updates jellyfish to 0.9.0
Adds mediafile 0.10.1
Updates munkres to 1.1.4
Updates musicbrainzngs to 0.7.1
Updates mutagen to 1.46.0
Updates pyyaml to 6.0
Updates unidecode to 1.3.6

libs/common/beetsplug/metasync/amarok.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # This file is part of beets.
 # Copyright 2016, Heinz Wiesinger.
 #
@@ -16,7 +15,6 @@
 """Synchronize information from amarok's library via dbus
 """
 
-from __future__ import division, absolute_import, print_function
 
 from os.path import basename
 from datetime import datetime
@@ -49,14 +47,14 @@ class Amarok(MetaSource):
         'amarok_lastplayed':  DateType(),
     }
 
-    queryXML = u'<query version="1.0"> \
+    query_xml = '<query version="1.0"> \
                     <filters> \
                         <and><include field="filename" value=%s /></and> \
                     </filters> \
                 </query>'
 
     def __init__(self, config, log):
-        super(Amarok, self).__init__(config, log)
+        super().__init__(config, log)
 
         if not dbus:
             raise ImportError('failed to import dbus')
@@ -72,7 +70,7 @@ class Amarok(MetaSource):
         # of the result set. So query for the filename and then try to match
         # the correct item from the results we get back
         results = self.collection.Query(
-            self.queryXML % quoteattr(basename(path))
+            self.query_xml % quoteattr(basename(path))
         )
         for result in results:
             if result['xesam:url'] != path: