New discards 25% of the random bits

[martin-sucha]

New uses bits 0-6 of each random byte (masks with 63) and the two high random bits are discarded.

I think it would be better not to discard randomness.

go-nanoid/gonanoid.go

Lines 89 to 97 in 0cc1b25

	bytes := make([]byte, size)
	_, err := rand.Read(bytes)
	if err != nil {
	return "", err
	}
	id := make([]rune, size)
	for i := 0; i < size; i++ {
	id[i] = defaultAlphabet[bytes[i]&63]
	}

It is possible to write a loop and output 4 characters per each 3 random bytes and handle the remainder separately.

Or maybe reuse the base64 encoding code from standard library.