bug#37207: guix.gnu.org returns Last-Modified = Epoch

[Ludovic Courtès]

Hello Guix,

Since the use of the ‘static-web-site’ service, which puts web site
files in the store, nginx returns a ‘Last-Modified’ header that can
trick clients into caching things forever:

--8<---------------cut here---------------start------------->8---
$ wget --debug -O /dev/null   https://guix.gnu.org/packages.json 2>&1 | grep 
Last
Last-Modified: Thu, 01 Jan 1970 00:00:01 GMT
--8<---------------cut here---------------end--------------->8---

We should tell nginx to do not emit ‘Last-Modified’, or to take the
state from the /srv/guix.gnu.org symlink, if possible.

Ludo’.