excluded_unless bug fix

[chargraves85]

Fixes Or Enhances

The verbiage in the documentation for both excluded_unless and required_unless is very similar. One would expect the opposite behavior for each when using multiple values of the same field that is being validated against.

For example:

This fails in all 3 cases in sample code

package main

import (
	"fmt"
	"github.com/go-playground/validator/v10"
)


type TestStruct struct {
	Foo int
	Bar string `validate:"excluded_unless=Foo 1 Foo 2"`
}

func main() {

	validator := validator.New()

	testA := TestStruct{
		Foo: 1,
		Bar: "test",
	}
	testB := TestStruct{
		Foo: 2,
		Bar: "test",
	}
	testC := TestStruct{
		Foo: 3,
		Bar: "test",
	}

	err := validator.Struct(testA)
	if err != nil {
		fmt.Println(err.Error())
	}

	err = validator.Struct(testB)
	if err != nil {
		fmt.Println(err.Error())
	}

	err = validator.Struct(testC)
	if err != nil {
		fmt.Println(err.Error())
	}

}

However, the equivilant opposite of this only fails in TestC

type TestStruct struct {
	Foo int
	Bar string `validate:"required_unless=Foo 1 Foo 2"`
}

func main() {

	validator := validator.New()

	testA := TestStruct{
		Foo: 1,
	}
	testB := TestStruct{
		Foo: 2,
	}
	
	err := validator.Struct(testA)
	if err != nil {
		fmt.Println(err.Error())
	}

	err = validator.Struct(testB)
	if err != nil {
		fmt.Println(err.Error())
	}

}

resolves #1306

[coveralls]

coverage: 74.291%. remained the same
when pulling ca3636f on chargraves85:issue-1306-excluded_unless-expectation-parity-with-required_unless
into a947377 on go-playground:master.