Fix path of python_callable_file and bump up AIRFLOW_VERSION

[mebelousov]

AIRFLOW_VERSION=2.0.0 and 2.0.2 produces some errors. Therefore I bump up AIRFLOW_VERSION

Broken DAG: [/usr/local/airflow/dags/example_dag_factory.py] Traceback (most recent call last):
  File "/dagfactory/dagbuilder.py", line 10, in <module>
    from airflow.contrib.operators.kubernetes_pod_operator import KubernetesPodOperator
  File "/usr/local/lib/python3.6/site-packages/airflow/contrib/operators/kubernetes_pod_operator.py", line 23, in <module>
    from airflow.providers.cncf.kubernetes.operators.kubernetes_pod import KubernetesPodOperator  # noqa
ModuleNotFoundError: No module named 'airflow.providers.cncf'

Traceback (most recent call last):
  File "/usr/local/bin/airflow", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.6/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/usr/local/lib/python3.6/site-packages/airflow/cli/cli_parser.py", line 47, in command
    func = import_string(import_path)
  File "/usr/local/lib/python3.6/site-packages/airflow/utils/module_loading.py", line 32, in import_string
    module = import_module(module_path)
  File "/usr/local/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/usr/local/lib/python3.6/site-packages/airflow/cli/commands/webserver_command.py", line 43, in <module>
    from airflow.www.app import cached_app, create_app
  File "/usr/local/lib/python3.6/site-packages/airflow/www/app.py", line 38, in <module>
    from airflow.www.extensions.init_views import (
  File "/usr/local/lib/python3.6/site-packages/airflow/www/extensions/init_views.py", line 29, in <module>
    from airflow.www.views import lazy_add_provider_discovered_options_to_connection_form
  File "/usr/local/lib/python3.6/site-packages/airflow/www/views.py", line 2836, in <module>
    class ConnectionFormWidget(FormWidget):
  File "/usr/local/lib/python3.6/site-packages/airflow/www/views.py", line 2839, in ConnectionFormWidget
    field_behaviours = json.dumps(ProvidersManager().field_behaviours)
  File "/usr/local/lib/python3.6/site-packages/airflow/providers_manager.py", line 397, in field_behaviours
    self.initialize_providers_manager()
  File "/usr/local/lib/python3.6/site-packages/airflow/providers_manager.py", line 129, in initialize_providers_manager
    self._discover_all_providers_from_packages()
  File "/usr/local/lib/python3.6/site-packages/airflow/providers_manager.py", line 149, in _discover_all_providers_from_packages
    self._provider_schema_validator.validate(provider_info)
  File "/usr/local/lib/python3.6/site-packages/jsonschema/validators.py", line 353, in validate
    raise error
jsonschema.exceptions.ValidationError: Additional properties are not allowed ('logo' was unexpected)

Failed validating 'additionalProperties' in schema['properties']['integrations']['items']:
    {'additionalProperties': False,
     'properties': {'external-doc-url': {'description': 'URL to external '
                                                        'documentation for '
                                                        'the integration.',
                                         'type': 'string'},
                    'how-to-guide': {'description': 'List of paths to '
                                                    'how-to-guide for the '
                                                    'integration. The path '
                                                    'must start with '
                                                    "'/docs/'",
                                     'items': {'type': 'string'},
                                     'type': 'array'},
                    'integration-name': {'description': 'Name of the '
                                                        'integration.',
                                         'type': 'string'},
                    'tags': {'description': 'List of tags describing the '
                                            "integration. While we're "
                                            'using RST, only one tag is '
                                            'supported per integration.',
                             'items': {'enum': ['apache',
                                                'aws',
                                                'azure',
                                                'gcp',
                                                'gmp',
                                                'google',
                                                'protocol',
                                                'service',
                                                'software',
                                                'yandex'],
                                       'type': 'string'},
                             'maxItems': 1,
                             'minItems': 1,
                             'type': 'array'}},
     'required': ['integration-name', 'external-doc-url', 'tags'],
     'type': 'object'}