[ci] Deprecate flake8 (#8409)

* [ci] Deprecate flake8

* Addressing @villebro's comments

superset/tasks/__init__.py

@@ -15,5 +15,4 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-from . import schedules  # noqa
-from . import cache  # noqa
+from . import cache, schedules

superset/tasks/cache.py

@@ -30,7 +30,6 @@ from superset.models.tags import Tag, TaggedObject
 from superset.tasks.celery_app import app as celery_app
 from superset.utils.core import parse_human_datetime
 
-
 logger = get_task_logger(__name__)
 logger.setLevel(logging.INFO)
 

superset/tasks/schedules.py

@@ -18,15 +18,16 @@
 
 """Utility functions used across Superset"""
 
+import logging
+import time
+import urllib.request
 from collections import namedtuple
 from datetime import datetime, timedelta
 from email.utils import make_msgid, parseaddr
-import logging
-import time
 from urllib.error import URLError
-import urllib.request
 
 import croniter
+import simplejson as json
 from dateutil.tz import tzlocal
 from flask import render_template, Response, session, url_for
 from flask_babel import gettext as __
@@ -34,8 +35,7 @@ from flask_login import login_user
 from retry.api import retry_call
 from selenium.common.exceptions import WebDriverException
 from selenium.webdriver import chrome, firefox
-import simplejson as json
-from werkzeug.utils import parse_cookie
+from werkzeug.http import parse_cookie
 
 # Superset framework imports
 from superset import app, db, security_manager