gitfiend: add livecheck (#103863)

* gitfiend: add livecheck

* Update gitfiend.rb

Co-authored-by: Miccal Matthews <miccal.matthews@gmail.com>

Casks/gitfiend.rb

@@ -3,10 +3,17 @@ cask "gitfiend" do
   sha256 "33a9de3a5a56f7851e699bb9f5eb4910d8bd14259ce60e71cba115e6ec968e07"
 
   url "https://gitfiend.com/resources/GitFiend-#{version}.dmg"
-  appcast "https://gitfiend.com/app-info"
   name "GitFiend"
+  desc "Git client"
   homepage "https://gitfiend.com/"
 
+  livecheck do
+    url "https://gitfiend.com/app-info"
+    strategy :page_match do |page|
+      JSON.parse(page)["version"]
+    end
+  end
+
   auto_updates true
 
   app "GitFiend.app"