videostream: use deprecate! instead of discontinued

Casks/v/videostream.rb

@@ -7,6 +7,8 @@ cask "videostream" do
   desc "Stream media from your computer to Chromecast"
   homepage "https://getvideostream.com/"
 
+  deprecate! date: "2023-12-17", because: :discontinued
+
   pkg "Videostream.pkg"
 
   uninstall launchctl: [
@@ -15,8 +17,4 @@ cask "videostream" do
             ],
             pkgutil:   "com.videostream",
             signal:    ["TERM", "com.videostream"]
-
-  caveats do
-    discontinued
-  end
 end