make SRecord class namespaced in RES::

[paneq]

It is accidentally unnamespaced

# @private
class SRecord
  def self.new(
    event_id:   SecureRandom.uuid,
    data:       SecureRandom.uuid,
    metadata:   SecureRandom.uuid,
    event_type: SecureRandom.uuid
  )
    RubyEventStore::SerializedRecord.new(
      event_id:   event_id,
      data:       data,
      metadata:   metadata,
      event_type: event_type,
    )
  end
end

RSpec.shared_examples :event_repository do |repository_class|
  # ...