ci: pin pipewire to a specific working commit

Big API break happens after this commit and we cannot
keep up right now.

.gitlab-ci.yml

@@ -10,6 +10,7 @@ build:
   script:
     # Build pipewire
     - cd pipewire
+    - git reset --hard b0932e687fc47e0872ca291531f2291d99042d70
     - meson . _build --prefix=/usr
         -Dpipewire-alsa=false -Dpipewire-pulseaudio=false -Dpipewire-jack=false
         -Djack=false -Dvulkan=false -Dgstreamer=false -Dbluez5=false -Dman=false