Version 2.4.0 release

In this release, the minor part of version is incremented since new symbols
are added for new APIs.

ALSA firewire-motu driver in Linux kernel v5.16 prepatch got new functions
to parse messages in isochronous packets from the target device. The
messages include state of DSP mixer and hardware meter information. The
The functions allow userspace software to read cached hardware meter
information and cached state of DSP mixer as well as to receive
notification about change for the state of DSP mixer. For userspace
application, UAPI header includes stuffs for the new functions.

In new release of libhinawa, some APIs are newly added to support the
functions. For compatibility reason, the source of libhinawa includes
the UAPI header.