incorrect range of timing patterns

[ksrnnb]

Last iteration m.size-finderPatternSize-1 for adding timing pattern is on separator pattern. It happens to be false, but it seems to be a misunderstanding.

I think it should be for i := finderPatternSize + 1; i < m.size-finderPatternSize-1; i++ {.

https://github.com/skip2/go-qrcode/blob/da1b6568686e89143e94f980a98bc2dbd5537f13/regular_symbol.go#L172-L181