Typo + Incorrect Info in strftime.ex

In timex/lib/format/datetime/formatters/strftime.ex, this section:

### Months

* `%m` - month number (1..12)
* `%b` - abbreviated month name (Jan..Dec, no padding)
* `%h` - same is `%b`

should instead state:
* `%m` - month number (01..12)
and (typo)
* `%h` - same as `%b`

This is minor but we do refer our customers to the strftime hex documentation published at https://hexdocs.pm/timex/Timex.Format.DateTime.Formatters.Strftime.html, and %m is padded by default.

{2012,8,1} |> Timex.format!("%m", :strftime)
"08"