Add PolicyTypes to allow-all egress policy (#7895)

`PolicyTypes` default to `["Egress", "Ingress"]`,
it doesn't make sense for egress-only policy to have `Ingress` as PolicyType.

docs/concepts/services-networking/network-policies.md

@@ -162,6 +162,8 @@ spec:
   podSelector: {}
   egress:
   - {}
+  policyTypes:
+  - Egress
 ```
 
 ### Default deny all ingress and all egress traffic
@@ -186,4 +188,4 @@ This ensures that even pods that aren't selected by any other NetworkPolicy will
 
 - See the [Declare Network Policy](/docs/tasks/administer-cluster/declare-network-policy/)
   walkthrough for further examples.
-- See more [Recipes](https://github.com/ahmetb/kubernetes-network-policy-recipes) for common scenarios enabled by the NetworkPolicy resource.
+- See more [Recipes](https://github.com/ahmetb/kubernetes-network-policy-recipes) for common scenarios enabled by the NetworkPolicy resource.