Authentication and authorization policies have been deprecated in favor of security policies.

Getting these deprecation warnings in Pyramid 2.0.
Are there any fixes please or advice on how best to resolve this?

```
DeprecationWarning: Authentication and authorization policies have been deprecated 
in favor of security policies. See "Upgrading Authentication/Authorization" in "What's New in Pyramid 2.0"
of the documentation for more information.
```

thanks
