pulse: use deprecate! instead of discontinued

Casks/p/pulse.rb

@@ -8,14 +8,12 @@ cask "pulse" do
   desc "Logger and network inspector"
   homepage "https://kean.blog/pulse/home"
 
+  deprecate! date: "2023-12-17", because: :discontinued
+
   app "Pulse.app"
 
   zap trash: [
     "~/Library/Application Scripts/com.github.kean.pulse",
     "~/Library/Containers/com.github.kean.pulse",
   ]
-
-  caveats do
-    discontinued
-  end
 end