blackbox: change year in logs to ISO 8601 format AFAIK, year/month/day is not a format than anyone uses. It seems more sensible to me to use ISO 8601, as that's standard and unambiguously year-month-day. Compatibility-wise, I think it's acceptable to change the default format. It's most for human consumption. It's plausible that a few tools parse this format, but it has already changed in the past (for instance to add the current revision). Differential Revision: https://phab.mercurial-scm.org/D12006