weston: switch to freerdp3

freerdp version 2 did get a security release with 2.11.7 last year, but is mostly unmaintained.
Weston serves as backend e.g. for sddm and thus is a security-critical component.
Moving it to a maintained version should be preferred.
Weston has support for both freerdp2 and freerdp3, and will use whichever backend is available [1].

[1] https://gitlab.freedesktop.org/wayland/weston/-/commit/89f3a8a71e0cf5ae9a1154cc168be7ebd97a64e7

pkgs/by-name/we/weston/package.nix

@@ -31,7 +31,7 @@
   pipewireSupport ? true,
   pipewire,
   rdpSupport ? true,
-  freerdp,
+  freerdp3,
   remotingSupport ? true,
   gst_all_1,
   vaapiSupport ? true,
@@ -91,7 +91,7 @@ stdenv.mkDerivation rec {
     ++ lib.optional lcmsSupport lcms2
     ++ lib.optional pangoSupport pango
     ++ lib.optional pipewireSupport pipewire
-    ++ lib.optional rdpSupport freerdp
+    ++ lib.optional rdpSupport freerdp3
     ++ lib.optionals remotingSupport [
       gst_all_1.gstreamer
       gst_all_1.gst-plugins-base