Add Zettlr at v1.2.3 (#62013)

* Add Zettlr at v1.2.3

* Update zettlr.rb

Casks/zettlr.rb

@@ -0,0 +1,19 @@
+cask 'zettlr' do
+  version '1.2.3'
+  sha256 'c7216c862175deb535edd18aa2770af07e36c8e2dd131fd8e74234a81e30e6f1'
+
+  # github.com/Zettlr/Zettlr was verified as official when first introduced to the cask
+  url "https://github.com/Zettlr/Zettlr/releases/download/v#{version}/Zettlr-macos-x64-#{version}.dmg"
+  appcast 'https://github.com/Zettlr/Zettlr/releases.atom'
+  name 'Zettlr'
+  homepage 'https://www.zettlr.com/'
+
+  app 'Zettlr.app'
+
+  zap trash: [
+               '~/Library/Application Support/zettlr',
+               '~/Library/Logs/Zettlr',
+               '~/Library/Preferences/com.zettlr.app.plist',
+               '~/Library/Saved Application State/com.zettlr.app.savedState',
+             ]
+end