Use timezone-aware datetimes

Author: lukasjuhrich

.flaskenv

@@ -1 +1,2 @@
 FLASK_APP=sipa:create_app
+FLASK_TEMPLATES_AUTO_RELOAD=true

sipa/initialization.py

@@ -2,7 +2,7 @@
 import logging.config
 import os
 import os.path
-from datetime import datetime
+from datetime import datetime, UTC
 
 import sentry_sdk
 from flask import g
@@ -96,7 +96,7 @@ def init_app(app, **kwargs):
         form_input_width_class=f"col-sm-{form_input_width}",
         form_input_offset_class=f"offset-sm-{form_label_width}",
         url_self=url_self,
-        now=datetime.utcnow()
+        now=datetime.now(UTC),
     )
     app.add_template_filter(render_links)