bug: panic, when using utf-8

[IAD]

Describe the bug

use the test:

func TestDefaultDriver_UTF8(t *testing.T) {
	detector := goaway.NewProfanityDetector().WithCustomDictionary(
		[]string{"anal", "あほ"}, // profanities
		[]string{"あほほ"},        // falsePositives
		[]string{"あほほし"},       // falseNegatives
	)

	message := "いい加減にしろ あほほし あほほ あほ anal ほ"
	expected := "いい加減にしろ **** あほほ ** **** ほ"

	isProfane := detector.IsProfane(message)
	require.True(t, isProfane)

	censored := detector.Censor(message)
	require.Equal(t, expected, censored)
}

What do you see?

panic at:
github.com/TwiN/go-away.(*ProfanityDetector).Censor(0xc000082f08, {0xf8f7c7, 0x3c})
.../github.com/TwiN/go-away/goaway.go:193 +0x7a5

What do you expect to see?

UTF-8 filtered as well as ASCII

List the steps that must be taken to reproduce this issue

use the test from the description

Version

v1.6.9

Additional information

No response

[TwiN]

Looks like a duplicate of #43 -- which likely has to do with the fact that UTF-8 characters can be more than one byte.

[stephenduke-care]

I attempted a fix on this here: #64