Change default date_options to 24 hour clock in TimestampedGeoJson

[andy23512]

According to the document of moment.js https://momentjs.com/docs/#/displaying/format/ , hh shows hours in 01 to 12, while HH shows hours in 00 to 23.
The original code use hh to display hour, and it causes the time 14:00 shown as 02:00. It's a pretty weird and misleading default option.
I think displaying 24-hour clock with HH is a better choice.
Any suggestion or anything else I need to do?

[Conengmo]

That makes sense, we can merge this. Two things:

• Please add a line to the changelog.
• While you're at it, maybe also change the date format to YYYY-MM-DD? That makes it even more ISO8601 compatible.

[andy23512]

Thanks for the suggestions.
The date format has been refined, and the change information has been added in changelog.

[Conengmo]

Merged! Thanks for the PR @andy23512.