Parsing with H and zero hour fails

[lukebaker]

Tested on node 14.15.1:

> fecha.parse("4/18/2021 01:41:42", "M/D/YYYY HH:mm:ss")
2021-04-18T05:41:42.000Z
> fecha.parse("4/18/2021 00:41:42", "M/D/YYYY HH:mm:ss")
2021-04-18T04:41:42.000Z
> fecha.parse("4/18/2021 1:41:42", "M/D/YYYY H:mm:ss")
2021-04-18T05:41:42.000Z
> fecha.parse("4/18/2021 0:41:42", "M/D/YYYY H:mm:ss")
null

The first three parse as expected, but the last one fails to parse. I would have expected it to be: 2021-04-18T04:41:42.000Z. Looking at the code, it appears the H when parsing uses the twoDigitsOptional regular expression, which only matches if it starts with a digit 1-9, whereas the documentation suggestions that H can parse 0 1 ... 22 23.

[taylorhakes]

Thanks for catching this @lukebaker . If you create a PR I will happily merge it

[taylorhakes]

Fixed issue in 4.2.2