docs: Update list of runtime dependencies

README.md

@@ -154,6 +154,10 @@ following dependencies at runtime:
   * Camera: scan QR codes during verification.
   * Location: send the user’s location in a conversation.
   * Settings: get the 12h/24h time format system preference.
+* GStreamer plugins:
+  * gst-plugin-gtk4 (gstgtk4): required to preview videos in the timeline and to present the output
+    of the camera.
+  * libgstpipewire with the `pipewiredeviceprovider`: used to list and access the cameras.
 * glycin: all images are loaded with this library so loaders for the different image formats need to
   be installed.
 

meson.build

@@ -25,7 +25,6 @@ dependency('gtk4', version: '>= 4.16')
 dependency('libadwaita-1', version: '>= 1.6')
 
 # Please keep these dependencies sorted.
-dependency('gstgtk4', version: '>= 0.13.0')
 dependency('gstreamer-1.0', version: '>= 1.20')
 dependency('gstreamer-app-1.0', version: '>= 1.20')
 dependency('gstreamer-base-1.0', version: '>= 1.20')