[nginx] list of versions is too big

[EtienneM]

from https://doc.scalingo.com/platform/deployment/buildpacks/nginx#specify-nginx-version

IMO we should only highlight the versions that are still officially supported.

In the case of Nginx, I think it should only be the LTS, hence it is only 1.26.

What do you think @Frzk ?

[Frzk]

I think we could keep both the stable (1.26.x) and mainline (1.27.y) versions, as we follow and maintain them. Would that be ok for you @EtienneM ?

[EtienneM]

Yes LGTM :)