Only the last field can have a fraction check doesn't always work

[mihaitodor]

The program below prints P3.5YT5.3S: 'Y' & 'S' only the last field can have a fraction because P3.5Y6M4DT12H30M5.3S passes the check, although I'm guessing it shouldn't.

package main

import "github.com/rickb777/date/period"

func main() {
        _, err := period.Parse("P3.5Y6M4DT12H30M5.3S", false)
        if err != nil {
                println(err.Error())
        }

        _, err = period.Parse("P3.5YT5.3S", false)
        if err != nil {
                println(err.Error())
        }
}

PS: Thank you for putting in the time to write this library!

[rickb777]

Resolved in v1.20.3.