parttime does not handle single digit month and year

I have a data set in which there are several date columns, and I need to use one (should be complete) for my analysis. Where the dates are completely missing in column 1, I try column 2 - if missing in column 2 I try column 3 etc until at the end I have a column of complete dates, using the first date available in order of preference.

I am using your package because one of my date columns (second last in order of preference) sometimes has incomplete dates, e.g. just a year or year and month. I need to impute a complete date (year, month, day) from these incomplete dates and then convert them to date, before considering them along with the others in order of preference.

To make matters even more complicated, some complete and incomplete dates have been written with a single digit for the month or day (leading 0 is missing). The one thing in my favour is that the order is always the same (i.e. always year, then month, then day, separated by a dash - so if it is the number or set of numbers after the first dash I know it is the month).

Suppose I have the following vector of dates:

```r
# Character vector of dates including some incomplete and some single digit dates:
x <- c("2019", "2023-10", "2024-09-15", "2024-7-3", "2022-5")

```

Now if I try to impute the date with `parttime::impute_date_min()` it will parse the first three but not the last two:

```r
# Impute date for partial dates:
y <- parttime::impute_date_min(x)
Warning message:
In vec_cast.partial_time.character(x, pttm, ..., format = format, :
Values could not be parsed (2 of 5 (40.0%)). Examples of unique failing formats:

'2024-7-3' '2022-5'

# Check what has happened:
> y
[5]>
[1] "2019-01-01" "2023-10-01" "2024-09-15" NA NA

```

If I use `lubridate::ymd()` it will correctly parse the complete dates with single digits but not the dates missing a whole element:

```r
# Convert to date format with lubridate:
z <- lubridate::ymd(x)
Warning message:
3 failed to parse.

# Check what has happened:
> z
[1] NA NA "2024-09-15" "2024-07-03" NA

```

I know that I could split the problematic date column into three (one each for year, month and day) then pad the single digit values with leading 0s, paste them back together as shown in [this Posit post](https://forum.posit.co/t/partial-dates-in-r/175268) and only then run them through `parttime::impute_date_min()`.

My question is: would it be possible to update the parttime package to handle these single digit cases, where the order of the date elements is already known?