Fix isISO8601 rejecting valid ordinal day 360

[naveentehrpariya]

The ordinal-date day sub-pattern 3([0-5]\d|6[1-6]) has a one-value gap: day 360 matches neither branch — [0-5]\d excludes 6x and 6[1-6] excludes x0 — so valid ISO 8601 ordinal dates such as 2019-360 are rejected.

validator.isISO8601('2019-359'); // true
validator.isISO8601('2019-360'); // false  ← bug
validator.isISO8601('2019-361'); // true

Day 360 exists in every year (all years have ≥ 365 days), so it is always a valid ordinal day. Brute-forcing 300–366 shows 360 is the only rejected value. isValidDate already accepts oDay <= 365/366, so the regex was the sole gate failing.

Changed 6[1-6] → 6[0-6] in both the standard and strict-separator regexes, and added 2019-360 to the valid fixtures.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (3d2f4b3) to head (8ecb378).

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #2787   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files          114       114           
  Lines         2587      2587           
  Branches       656       656           
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  Hits          2587      2587           

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