Allow -0 as an octet integer value

[nakabonne]

Currently, giving -0 causes panic. This PR is a tiny fix for that.

package main

import (
	"bytes"
	"fmt"
	"log"

	goyaml "github.com/goccy/go-yaml"
)

func main() {
	yml := []byte(`foo: -0`)
	path := "$.foo"
	p, err := goyaml.PathString(path)
	if err != nil {
		log.Fatal(err)
	}

	var value interface{}
	if err := p.Read(bytes.NewReader(yml), &value); err != nil {
		log.Fatal(err)
	}
}

[goccy]

Thank you !!!