Not compliant with RFC4122 spec

[rogerclermont]

The generated variant for nu7hatch uuids does not seem to be compliant with the RFC 4122 spec; this results in all nu7hatch uuids failing any RFC4122-based compliance/validation checks.

Quoting the spec (from https://tools.ietf.org/html/rfc4122#section-4.1.1)

4.1.1.  Variant
...

Msb0  Msb1  Msb2  Description
...
    1     0     x    The variant specified in this document.
...

Note though that the variant of nu7hatch uuids has these MSB bits set to 01, rather than 10; example code:

package main

import (
	"fmt"

	"github.com/nu7hatch/gouuid"
)

func main() {

	// create a new v4 uuid
	v4UUID, err := uuid.NewV4()
	if err != nil {
		panic(err.Error())
	}

	// RFC4122 states the variant format should be MSB0==1 and MSB1==0;
	// https://tools.ietf.org/html/rfc4122#section-4.1.1
	fmt.Printf("%08b\n", v4UUID.Variant())

}

Output:
01000000

[cyberkryption]

Please fix this as it breaks many other projects that rely on govalidator. Also the fact that it is incompatible with main go uuid library is poor.