Update setup.py. Add config directory to package_data

[Sparkymann]

При билде не попадает директория с конфигом, из-за этого не получается использовать плагин OfflineReport.
Stack:

Traceback (most recent call last):
  File \"/usr/local/lib/python3.9/dist-packages/yandextank/validator/validator.py\", line 41, in load_plugin_schema
    return load_yaml_schema(
  File \"/usr/local/lib/python3.9/dist-packages/yandextank/validator/validator.py\", line 30, in load_yaml_schema
    file_content = read_resource(path)
  File \"/usr/local/lib/python3.9/dist-packages/yandextank/common/util.py\", line 34, in read_resource
    with open(path, file_open_mode) as f:
FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/lib/python3.9/dist-packages/yandextank/plugins/OfflineReport/config/schema.yaml'