Bump to version 20!

app/src/main/AndroidManifest.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="org.galexander.sshd"
-      android:versionCode="19"
-      android:versionName="19">
+      android:versionCode="20"
+      android:versionName="20">
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

doc/index.html

@@ -179,7 +179,7 @@ regular <tt>rsa</tt> key for greatest compatibility.
 <h2>Change Log</h2>
 
 <ul>
-<li> <b>2019/06/XXX Version 20:</b> Update SDK.  Support x86_64, arm64.
+<li> <b>2019/06/16 Version 20:</b> Update SDK.  Support x86_64, arm64.
 Fix finding support libraries.  Fix colors again.  Fix start-on-boot on
 new Android.  Update to dropbear 2019.78.
 <li> <b>2018/05/19 Version 19:</b> Use the app-private directory by