cerbero: Fix packaging on macOS

Now that libnice is built with Meson, the gstreamer plugin built by
it uses a dylib suffix.
10 jobs for macos-packaging in 48 minutes and 22 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Preparation
passed #85860
manifest

00:00:36

 
  Build
canceled #85957
cerbero deps fedora x86_64

canceled #85956
cerbero deps windows x86

passed #85863
cerbero deps windows x86_64

00:47:45

failed #85955
cerbero deps fedora x86_64

01:00:00

failed #85861
cerbero deps fedora x86_64

01:00:00

failed #85862
cerbero deps windows x86

01:00:01

 
  Full Builds
skipped #85865
build cerbero cross win32
skipped #85866
build cerbero cross win64
skipped #85864
build cerbero fedora x86_64