Add PDF Element Pro v6.6.1
user
```ruby
cask "pdfelementpro" do
  version "6.6.1,2992"
  sha256 "1b4ea505e82cd01f5aacb0e7501d0999cbdf28159eb3874f1710041b5523a40b"

  url "http://download.wondershare.com/cbs_down/mac-pdfelement#{version.major}-pro_full#{version.after_comma}.dmg"
  name "Wondershare PDFelement Professional for Mac"
  homepage "https://pdf.wondershare.com/"

  app "PDFelementPro#{version.major}.app"
end
```
assistant