fix: add POST_NOTIFICATIONS permission to fix TeamNewPipe#16

Author: NullPointerException

app/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
 
     <uses-feature
         android:name="android.hardware.touchscreen"