ISO
ISO 8601 extended format.
Examples of date/time in ISO 8601 format:
2020-08-30T18:43
+12020-08-30T18:43:00
0000-08-30T18:43:00.5
-0001-08-30T18:43:00.123456789
When formatting, seconds are always included, even if they are zero. Fractional parts of the second are included if non-zero.
Guaranteed to parse all strings that LocalDateTime.toString produces.