SegmentationUpid.ASCIIValue() has issue in v1.4.3

[veloandy]

The ASCIIValue() method in release scte35-go v1.4.3 panics with

panic: runtime error: index out of range [0] with length 0

from scte35-go@v1.4.3/pkg/scte35/segmentation_upid.go:176

This worked without issue in version 1.4.2.

This is a quick program to reproduce:

package main

import (
	"fmt"

	"github.com/Comcast/scte35-go/pkg/scte35"
)

func main() {
	upid := scte35.SegmentationUPID{
		Type:  0x09,
		Value: "SIGNAL:z1sFOMjCnV4AAAAAAAABAQ==",
	}
	fmt.Printf("%+v\n", upid)
	fmt.Printf("%+v\n", upid.ASCIIValue()) // <- panics with index out of range in scte35.go v1.4.3. Was OK in v1.4.2.
}

[blahspam]

Thanks @veloandy. Fixed in v1.4.4.