Bad default sftp subsystem config in sshd_config

By default on Alpine Edge, /etc/ssh/sshd_config has this line nearing the end:

Subsystem	sftp	/usr/lib/ssh/sftp-server

If the system doesn't have openssh-sftp-server package installed, this fails silently. On the other hand, setting the sftp subsystem to internal-sftp doesn't require the additional package and works with just the standalone openssh-server.

I think the default should be changed to internal-sftp, to improve compatibility.