Add more date patterns and changed to a more lenient day and month parsing

[bkiers]

Add more date patterns and changed to a more lenient day and month parsing: MM and dd changed to M and d. Now not only things like 2024-02-09 are parsed correctly, but also 2024-2-9

Fixes #309

Tested with Ruby:

# frozen_string_literal: true
require 'liquid'

tests = [
  "now",
  "today",
  "1 March",
  "MAR",
  "MARCH",
  "2024 MAR",
  "2 mar",
  "2 MAR",
  "march 2nd",
  "MARCH 2",
  "MARCH 2nd",
  "MARCH 3RD",
  "MARCH 4th",
  "MARCH 5th",
  "MARCH 10th",
  "2010-10-31",
  "Aug 2000",
  "Aug 31",
  "Wed Nov 28 14:33:20 2001",
  "Wed, 05 Oct 2011 22:26:12 -0400",
  "Wed, 05 Oct 2011 02:26:12 GMT",
  "Nov 29 14:33:20 2001",
  "05 Oct 2011 22:26:12 -0400",
  "06 Oct 2011 02:26:12 GMT",
  "2011-10-05T22:26:12-04:00",
  "0:00",
  "1:00",
  "01:00",
  "12:00",
  "16:30",
  "3/2024",
  "01/03",
  "03/31",
  "2001/03",
  "01/2003",
  "70-10-31"
]

tests.each do |test|
  template_string = "{% assign v1 = '#{test}' | date: '%s' %}{% assign v2 = '#{test}' | date: '%b %d, %y' %}{{ v1 }}, {{ v2 }}"
  template = Liquid::Template.parse(template_string)
  puts "#{test} -> #{template.render({})}"
end

which prints:

now -> 1731957693, Nov 18, 24
today -> 1731957693, Nov 18, 24
1 March -> 1709247600, Mar 01, 24
MAR -> 1709247600, Mar 01, 24
MARCH -> 1709247600, Mar 01, 24
2024 MAR -> 1709247600, Mar 01, 24
2 mar -> 1709334000, Mar 02, 24
2 MAR -> 1709334000, Mar 02, 24
march 2nd -> 1709334000, Mar 02, 24
MARCH 2 -> 1709334000, Mar 02, 24
MARCH 2nd -> 1709334000, Mar 02, 24
MARCH 3RD -> 1709420400, Mar 03, 24
MARCH 4th -> 1709506800, Mar 04, 24
MARCH 5th -> 1709593200, Mar 05, 24
MARCH 10th -> 1710025200, Mar 10, 24
2010-10-31 -> 1288476000, Oct 31, 10
Aug 2000 -> 965080800, Aug 01, 00
Aug 31 -> 1725055200, Aug 31, 24
Wed Nov 28 14:33:20 2001 -> 1006954400, Nov 28, 01
Wed, 05 Oct 2011 22:26:12 -0400 -> 1317867972, Oct 05, 11
Wed, 05 Oct 2011 02:26:12 GMT -> 1317781572, Oct 05, 11
Nov 29 14:33:20 2001 -> 1007040800, Nov 29, 01
05 Oct 2011 22:26:12 -0400 -> 1317867972, Oct 05, 11
06 Oct 2011 02:26:12 GMT -> 1317867972, Oct 06, 11
2011-10-05T22:26:12-04:00 -> 1317867972, Oct 05, 11
0:00 -> 1731884400, Nov 18, 24
1:00 -> 1731888000, Nov 18, 24
01:00 -> 1731888000, Nov 18, 24
12:00 -> 1731927600, Nov 18, 24
16:30 -> 1731943800, Nov 18, 24
3/2024 -> 1709247600, Mar 01, 24
01/03 -> 1704236400, Jan 03, 24
03/31 -> 1711839600, Mar 31, 24
2001/03 -> 983401200, Mar 01, 01
01/2003 -> 1041375600, Jan 01, 03
70-10-31 -> 26175600, Oct 31, 70