dotenv parser shows wrong line number after inheritance syntax

[panzi]

If the inheritance syntax is used the line number isn't incremented.

Meaning, if rune == '\n' here, then p.line needs to be incremented: https://github.com/compose-spec/compose-go/blob/9d0d133e13d0955e27520c6317d08822b7c5de5f/dotenv/parser.go#L120

I'd add that before the successful return at the end of the function, so that if an error is reported it points at the correct line:

    if inherited {
        p.line++
    }
    return key, cutset, inherited, nil
}

[ndeloof]

Would you offer us a PR to get this fixed ?