v2.0.0

• Add support for responsive widths.
  • Setting global default widths for all snapshots:
    
    Percy.config.default_widths = [320, 1280]
  • Or override on a per-snapshots basis:
    
    Percy::Capybara.snapshot(page, name: 'homepage', widths: [320, 1280])
• Update internal error handling and percy-client dependency.
• Breaking change: removed deprecated flow where create_snapshot would initialize a build if not already created. Users must explicitly call Percy::Capybara.initialize_build (or use the RSpec require) at the beginning of test suites, which was required for parallel test support.