Bump version to 0.0.5
Support shorter config when no observers are needed

It is now possible to skip the nested hash for
action configuration:

dispatcher = Substation::Dispatcher.coerce({
  :some_use_case => App::SomeUseCase
}, env)

dispatcher = Substation::Dispatcher.coerce({
  :some_use_case => Proc.new { |request| request.success(:data) }
}, env)