Deprecation warning thrown on codegate certificates code

[yrobla]

/app/src/codegate/ca/codegate_ca.py:321: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
builder = builder.not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=365))