Update index.rst
During the meeting it was clear from the Nix team that they wanted our tutorial to point to https://nix.dev.
source: https://github.com/NixOS/nix.dev/issues/284#issuecomment-1198130228
Edited by FAURE Adrien
GitLab upgrade completed. Current version is 18.5.4
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https://about.gitlab.com/releases/2025/10/16/gitlab-18-5-released/
During the meeting it was clear from the Nix team that they wanted our tutorial to point to https://nix.dev.
source: https://github.com/NixOS/nix.dev/issues/284#issuecomment-1198130228