private int calculateNewReplicaCount(final int currentReplicas, final ScaleAction action) {
        return switch (action.getActionType()) {
            case SCALE_UP -> currentReplicas + 1;
            case SCALE_DOWN -> Math.max(0, currentReplicas - 1);
            default -> currentReplicas;
        };
    }
scale by number.

@param replicaCount replicaCount
shenyu-admin/src/main/java/org/apache/shenyu/admin/scale/scaler/KubernetesScaler.java