label selector matches all objects. A null label selector matches
                    no objects.
                  properties:
                    matchExpressions:
                      description: matchExpressions is a list of label selector requirements.
                        The requirements are ANDed.
                      items:

  // operator is "In", and the values array contains only "value". The requirements are ANDed.
  // +optional
  map<string, string> matchLabels = 1;

  // matchExpressions is a list of label selector requirements. The requirements are ANDed.
  // +optional
  repeated LabelSelectorRequirement matchExpressions = 2;
}