increment version number to 0.21.8

NEWS

+ver 0.21.8 (not yet released)
+
 ver 0.21.7 (2019/04/03)
 * input
   - qobuz/tidal: scan tags when loading a playlist

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="29"
-          android:versionName="0.21.7">
+          android:versionCode="30"
+          android:versionName="0.21.8">
 
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="26"/>
 

doc/conf.py

@@ -38,7 +38,7 @@ author = 'Max Kellermann'
 # built documents.
 #
 # The short X.Y version.
-version = '0.21.7'
+version = '0.21.8'
 # The full version, including alpha/beta/rc tags.
 release = version
 

meson.build

 project(
   'mpd',
   ['c', 'cpp'],
-  version: '0.21.7',
+  version: '0.21.8',
   meson_version: '>= 0.49.0',
   default_options: [
     'c_std=c99',