cosmic-osd: add updateScript

pkgs/by-name/co/cosmic-osd/package.nix

@@ -7,6 +7,7 @@
   pulseaudio,
   udev,
   wayland,
+  nix-update-script,
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -33,6 +34,15 @@ rustPlatform.buildRustPackage rec {
 
   env.POLKIT_AGENT_HELPER_1 = "/run/wrappers/bin/polkit-agent-helper-1";
 
+  passthru.updateScript = nix-update-script {
+    extraArgs = [
+      "--version"
+      "unstable"
+      "--version-regex"
+      "epoch-(.*)"
+    ];
+  };
+
   meta = with lib; {
     homepage = "https://github.com/pop-os/cosmic-osd";
     description = "OSD for the COSMIC Desktop Environment";