Bump utils to bring in fix for optional placeholder bug

See https://github.com/alphagov/notifications-utils/pull/878 for
details.

Changes we had to make for our app and tests to work correctly
after the dependency updates:

1. Update emergency alerts polygons test because we changed
how exact we are with locations of the points on the map.

2. Use Flask's g object to set additional request attributes

So far we have been storing them in _request_ctx_stack which is
an innard for Flask's request context.

Because of major update to Werkzeug dependency, which Flask relies
on, the way we were using it stopped working, so we had a new
way to set those values.
The way we set those values now, by using g object, seems to also
be favoured in Flask documentation:
https://flask.palletsprojects.com/en/1.1.x/reqcontext/#how-the-context-works

app/__init__.py

@@ -7,7 +7,6 @@ from time import monotonic
 
 from celery import current_task
 from flask import (
-    _request_ctx_stack,
     current_app,
     g,
     has_request_context,
@@ -69,8 +68,8 @@ metrics = GDSMetrics()
 
 notification_provider_clients = NotificationProviderClients()
 
-api_user = LocalProxy(lambda: _request_ctx_stack.top.api_user)
-authenticated_service = LocalProxy(lambda: _request_ctx_stack.top.authenticated_service)
+api_user = LocalProxy(lambda: g.api_user)
+authenticated_service = LocalProxy(lambda: g.authenticated_service)
 
 CONCURRENT_REQUESTS = Gauge(
     'concurrent_web_request_count',

app/authentication/auth.py

@@ -1,6 +1,6 @@
 import uuid
 
-from flask import _request_ctx_stack, current_app, g, request
+from flask import current_app, g, request
 from gds_metrics import Histogram
 from notifications_python_client.authentication import (
     decode_jwt_token,
@@ -140,8 +140,8 @@ def requires_auth():
             raise AuthError("Invalid token: API key revoked", 403, service_id=service.id, api_key_id=api_key.id)
 
         g.service_id = service.id
-        _request_ctx_stack.top.authenticated_service = service
-        _request_ctx_stack.top.api_user = api_key
+        g.api_user = api_key
+        g.authenticated_service = service
 
         current_app.logger.info('API authorised for service {} with api key {}, using issuer {} for URL: {}'.format(
             service.id,