Raise the version of liborc to 0.4.31
Raise the version of liborc to 0.4.31

Otherwise it doesn't compile with newer gcc:
there was a minor error in orc/orctarget.h -
enum OrcTargetPowerPCFlags was declared as a
variable and not as a type.

This error was fixed in a commit
0b1a288835d6a3b6d52f77e0c2e86d685de6526e
of
https://gitlab.freedesktop.org/gstreamer/orc.git

fluendo/cerbero,fluendo/cerbero,fluendo/cerbero,fluendo/cerbero,fluendo/cerbero