[vconone] Notice people to update year

[dayo09]

What?

vconone is a library that helps printing out version information with copyright.
It's copyright year should be manually updated.
However, it's very hard to notice this job.

• [vconone] Update copyright year #14587 from 2023 to 2025: Updated 1 year later
• [vconone] Update copyright year #11322 from 2022 to 2023: Updated 8 months later

Therefore, I suggest comparing vconone year and system clock's year in unittest.

int get_current_year(void)
{
  auto now = std::chrono::system_clock::now();
  std::time_t current_time = std::chrono::system_clock::to_time_t(now);
  std::tm *timeinfo = std::localtime(&current_time);

  int year = timeinfo->tm_year + 1900;
  return year;
}

• pros
  • We can precisely give out our copyright information.
• cons
  • Unit test can result in failure (false-negative) if the machine's system clock is wrong.
  • On the first day of the year, we may confront CI failure without noticing.
    • Maybe we can make give it a term for 1 month or so. (ex. Fail the test if it's not fixed until Feb of the next year)

DRAFT: #14588