No registry logout function

Using the command line podman there exits an command to log out from an registry:
`podman logout `
But via the API I don't see an function call for it.
So until now you can login via:
```
with podman.PodmanClient() as pm:
pm.login(password=self._container_registry_credentials["token"],
username=self._container_registry_credentials["user"], registry=f"https://{self._container_registry}")
```
But after the program quits you are still logged in into the registry.