Add cask for 1Password 3
user
```ruby
class OnePassword3 < Cask
  url 'https://d13itkw33a7sus.cloudfront.net/dist/1P/mac/1Password-3.8.21.zip'
  homepage 'https://agilebits.com/onepassword'
  version '3.8.21'
  sha1 '5ead1fcfeaca615c8b7ed3ca5c5ff681edb9ef56'
  link '1Password.app'
end
```
assistant