Auto-generate date in gemspec file.

  s.name = 'jsduck'

  s.version = '5.0.0.beta01'

  s.date = '2013-02-25'

  s.date = Time.new.strftime('%Y-%m-%d')

  s.summary = "Simple JavaScript Duckumentation generator"

  s.description = "Documentation generator for Sencha JS frameworks"

  s.homepage = "https://github.com/senchalabs/jsduck"