candybar: use deprecate! instead of discontinued

Casks/c/candybar.rb

@@ -7,6 +7,8 @@ cask "candybar" do
   desc "Tool to modify file icons"
   homepage "https://panic.com/blog/candybar-mountain-lion-and-beyond/"
 
+  deprecate! date: "2023-12-17", because: :discontinued
+
   app "CandyBar.app"
 
   zap trash: [
@@ -18,7 +20,6 @@ cask "candybar" do
   ]
 
   caveats do
-    discontinued
     free_license "https://panic.com/bin/setup.php/cb3/PPQA-YAMA-E3KP-VHXG-B6AL-L"
   end
 end