Please review and translate: DebConf20 closing announcement

Dear all
The DebConf20 closing announcement is ready for review and translations:

https://salsa.debian.org/publicity-team/bits/-/blob/master/content/2020/debconf20-closes.md

We may do some last minute editions but I think not much more than what
you can see now.

I'll add a wml file to the English folder in the announcements repo
later; feel free to work only one of them, the format you better like
(bits repo in markdown, announcements repo in html) and I'll do my best
to keep both English documents in sync, and copy and adapt translations
when publishing in each channel.

Kind regards,