removed lt and gt as operators (#4152)

* removed lt and gt as operators

* replace lt and gt for node-affinfity

* updated based on bsalamat review

docs/concepts/configuration/assign-pod-node.md

@@ -188,7 +188,7 @@ label having key "security" and value "S2".) See the [design doc](https://github
 for many more examples of pod affinity and anti-affinity, both the `requiredDuringSchedulingIgnoredDuringExecution`
 flavor and the `preferredDuringSchedulingIgnoredDuringExecution` flavor.
 
-As with node affinity, the legal operators for pod affinity and anti-affinity are `In`, `NotIn`, `Exists`, `DoesNotExist`, `Gt`, `Lt`.
+The legal operators for pod affinity and anti-affinity are `In`, `NotIn`, `Exists`, `DoesNotExist`.
 
 In principle, the `topologyKey` can be any legal label value. However,
 for performance reasons, only a limited set of topology keys are allowed.