Fix vulnerabilities. Set minimum Python version to 3.6.8 (#576)

* Fix vulnerabilities. Set minimum Python version to 3.6.8
* Fix tests

hydrus/app_factory.py

@@ -2,12 +2,9 @@
 import uuid
 from flask_cors import CORS
 from flask_restful import Api
-from hydrus_logger import HydrusLogger
 from hydrus.resources import (Index, Vocab, Contexts, Entrypoint,
                               ItemCollection, Item, Items, ItemMember)
 
-logger = HydrusLogger().get_logger()
-
 
 def app_factory(api_name: str = "api", vocab_route: str = "vocab") -> Flask:
     """
@@ -23,16 +20,6 @@ def app_factory(api_name: str = "api", vocab_route: str = "vocab") -> Flask:
     app.url_map.strict_slashes = False
     api = Api(app)
 
-    @app.after_request
-    def logging_request_response(response):
-        if response.location and response.status_code != 302:
-            logger.info(" {} {}:{} Object_created_at : {}, status_code : {} "
-                        .format(uuid.uuid4(), request.method, request.path, response.location, response.status))
-        else:
-            logger.info(" {} {}:{}  status_code : {} "
-                        .format(uuid.uuid4(), request.method, request.path, response.status))
-        return response
-
     # Redirecting root_path to root_path/api_name
     if api_name:
         @app.route("/")