increment version number to 0.21.21

NEWS

+ver 0.21.21 (not yet released)
+
 ver 0.21.20 (2020/02/16)
 * decoder
   - audiofile, ffmpeg, sndfile: handle MIME type "audio/wav"

android/AndroidManifest.xml

@@ -2,8 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="org.musicpd"
           android:installLocation="auto"
-          android:versionCode="43"
-          android:versionName="0.21.20">
+          android:versionCode="44"
+          android:versionName="0.21.21">
 
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28"/>
 

doc/conf.py

@@ -38,7 +38,7 @@ author = 'Max Kellermann'
 # built documents.
 #
 # The short X.Y version.
-version = '0.21.20'
+version = '0.21.21'
 # The full version, including alpha/beta/rc tags.
 release = version
 

meson.build

 project(
   'mpd',
   ['c', 'cpp'],
-  version: '0.21.20',
+  version: '0.21.21',
   meson_version: '>= 0.49.0',
   default_options: [
     'c_std=c99',