[openstreetmap/openstreetmap-website] Add banner for OSM16 events. (#2745)

[naveenpf]

![OpenStreetMap_16th_birthday_v2](https://user-images.githubusercontent.com/12662835/89138479-5bf7e600-d559-11ea-9c61-ae08c046a582.jpg)

Link:- https://wiki.openstreetmap.org/wiki/OpenStreetMap_16th_Anniversary_Birthday_party

Till Aug 9, 2020 

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/openstreetmap-website/issues/2745
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/rails-dev/attachments/20200802/cd9b941e/attachment.htm>