ci: use the same os image as pipewire and build pw with minimal features

Stick to an OS that we know it works for the pipewire CI and
avoid building too much as we don't need them (and might trigger
failures that are not of any relevance for wireplumber)

.gitlab-ci.yml

@@ -1,10 +1,7 @@
-image: fedora:rawhide
+image: registry.freedesktop.org/pipewire/pipewire/fedora:31
 
 variables:
-  DEPENDENCIES: gtk-doc meson gcc gcc-c++ glibc-devel make dbus-devel
+  DEPENDENCIES: gtk-doc gobject-introspection-devel
-                gstreamer1-plugins-base-devel sbc-devel bluez-libs-devel
-                alsa-lib-devel pulseaudio-libs-devel systemd-devel git
-                gobject-introspection-devel
 
 build:
   before_script:
@@ -13,7 +10,10 @@ build:
   script:
     # Build pipewire
     - cd pipewire
-    - meson . _build --prefix=/usr -Dpipewire-jack=false -Djack=false -Dvulkan=false
+    - meson . _build --prefix=/usr
+        -Dpipewire-alsa=false -Dpipewire-pulseaudio=false -Dpipewire-jack=false
+        -Djack=false -Dvulkan=false -Dgstreamer=false -Dbluez5=false -Dman=false
+        -Dvideotestsrc=true -Daudiotestsrc=true
     - ninja -C _build
     - ninja -C _build install
     - cd ..