The first part of the h2s/greencard#1, this stops the first fatal error

The core problem remains, but with this tweak execution manages to struggle
along for an entire two further lines before dying of another
Encoding::Compatibility

    Failure/Error: vcard = GreenCard::Vcard.decode(vcard_text)
    Encoding::CompatibilityError:
      incompatible encoding regexp match (ASCII-8BIT regexp with UTF-8 string)
    # ./lib/greencard/vcard.rb:669:in `==='
    # ./lib/greencard/vcard.rb:669:in `decode'
    # ./spec/greencard/vcard_spec.rb:12:in `block (2 levels) in <top (required)>'

It's not much, but it's a start.