NoMethodError if the xcode project has no target attributes

[eddy-lau]

NoMethodError: [!] undefined method `[]' for nil:NilClass
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-plugin-cosigner-2.0.1/lib/fastlane/plugin/cosigner/actions/cosigner_action.rb:21:in `run'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:257:in `block (2 levels) in execute_action'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/actions/actions_helper.rb:50:in `execute_action'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:236:in `block in execute_action'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:231:in `chdir'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:231:in `execute_action'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:157:in `trigger_action_by_name'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/fast_file.rb:148:in `method_missing'
  Fastfile:24:in `block (2 levels) in parsing_binding'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/lane.rb:33:in `call'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:49:in `block in execute'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:45:in `chdir'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/runner.rb:45:in `execute'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/lane_manager.rb:57:in `cruise_lane'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/command_line_handler.rb:36:in `handle'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/commands_generator.rb:108:in `block (2 levels) in run'
  /usr/local/lib/ruby/gems/2.5.0/gems/commander-fastlane-4.4.6/lib/commander/command.rb:178:in `call'
  /usr/local/lib/ruby/gems/2.5.0/gems/commander-fastlane-4.4.6/lib/commander/command.rb:153:in `run'
  /usr/local/lib/ruby/gems/2.5.0/gems/commander-fastlane-4.4.6/lib/commander/runner.rb:476:in `run_active_command'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane_core/lib/fastlane_core/ui/fastlane_runner.rb:75:in `run!'
  /usr/local/lib/ruby/gems/2.5.0/gems/commander-fastlane-4.4.6/lib/commander/delegates.rb:15:in `run!'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/commands_generator.rb:333:in `run'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/commands_generator.rb:42:in `start'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/fastlane/lib/fastlane/cli_tools_distributor.rb:98:in `take_off'
  /usr/local/lib/ruby/gems/2.5.0/gems/fastlane-2.85.0/bin/fastlane:20:in `<top (required)>'
  /usr/local/bin/fastlane:23:in `load'
  /usr/local/bin/fastlane:23:in `<top (required)>'