Add badges with the Kirby version number for old and new docs

Last weekend I played around with an own version of using “Kirby 2.3.0 final”.

First I followed but don’t got it working.

Afterwards I have found, which leads me to running code, after I have found that the second param at has to be written in lowercase!

Now I suggest to add badges with the Kirby versions (e.g. like “< 2.3.0”) to the old docs and the other way round like “2.3.0+” to the new docs, particularly at A link to the new docs there would be great.
May be someone can add a comment at that the second param (e.g. “css” in my case) needs to be in lowercase.

Thank you for the suggestion, we will consider it.