osmium: add update script (#516912)

pkgs/by-name/os/osmium/package.nix

@@ -24,14 +24,18 @@
   gtk3,
   libnotify,
   libpulseaudio,
+  writeShellApplication,
+  curl,
+  yq,
+  common-updater-scripts,
 }:
 
 stdenv.mkDerivation rec {
   pname = "osmium";
-  version = "0.0.19";
+  version = "0.0.19-alpha";
 
   src = fetchurl {
-    url = "https://updater.osmium.chat/Osmium-${version}-alpha-x64.tar.gz";
+    url = "https://updater.osmium.chat/Osmium-${version}-x64.tar.gz";
     hash = "sha256-Qwh6K2QlJJapqR0BkaA0LvwLEsqktnLzOnyJg+7sMFo=";
   };
 
@@ -98,6 +102,21 @@ stdenv.mkDerivation rec {
     startupWMClass = "Osmium";
   };
 
+  passthru = {
+    updateScript = lib.getExe (writeShellApplication {
+      name = "update-osmium";
+      runtimeInputs = [
+        curl
+        yq
+        common-updater-scripts
+      ];
+      text = ''
+        version="$(curl -s https://updater.osmium.chat/alpha-linux.yml | yq .version)"
+        update-source-version osmium "${version}"
+      '';
+    });
+  };
+
   meta = {
     description = "Globally distributed community messaging and voice/video platform";
     homepage = "https://osmium.chat/";