Issue with sha256('abc£123')

[ariutta]

The currency pound sign £ is character code 163 (<255), but this library returns the wrong value:

sha256('abc£123');

actual: 25c772bc82b146ed5c1552ec42fc67a1a6140042c3cf1e95721ff0a8b38864f3 expected either: 57c797465642f80fd87c5caa0838c79db1d14b52c6f79819f811aa7550aa4c4d or undefined