Log Message:
libopus; Update to 1.4

Changelog:
This Opus 1.4 major release brings the following improvements and fixes:

  * Improved tuning of the Opus in-band FEC (LBRR). See the issue for details
  * Added a OPUS_SET_INBAND_FEC(2) option that turns on FEC, but does not
    force SILK mode (FEC will be disabled in CELT mode)
  * Improved tuning and various fixes to DTX
  * Added Meson support, improved CMake support In addition to the
    improvements above, this release includes many minor bug fixes.