Document meeting schedule

[dlqqq]

cc @rpwagner @Carreau

We should document the meeting schedule more clearly, especially as we will change it in 2025, as concluded in this morning's Security WG call.

If I recall correctly, the plan for 2025 is to meet weekly on Tuesdays, alternating between public & private calls respectively.

• 7 Jan 2025: first public call (for the Jupyter Security Working Group)
• 14 Jan 2025: first private call (for the Jupyter Security Council)
• 21 Jan 2025: public call
• 28 Jan 2025: private call
• etc.

Maintaining a table of dates may require too much manual effort. @rpwagner, it would be great if you could set up those 2 biweekly meeting series & include a link to those in our README. That way, anybody interested could click on those links to add the series to their calendar.