nix: Update to Python 3.12

[echoix]

My initial goal was to trigger renovate to recognize the nix packages again, as it isn't able to create a lock file update yet.
I then changed the files, run nix flake update, then ran a build.

[echoix]

@imincik Does this look correct?

[imincik]

@echoix Sorry, I am not sure why I constantly notice notifications from this repo too late. Please ping me over Matrix next time I am not responding.

@imincik Does this look correct?

I am not sure what exactly is the main goal of this PR.

To update to Python 3.12, it is enough to change python311Packages to python312Packages as you did. It is even better to change it to python3Packages which will point to the default Python 3 version in nixpkgs (this is what we have in nixpgks/grass package).

To update to the latest rolling version of nixpkgs (nixpkgs-unstable) you have to run nix flake update.

Also, I suggest to sync from time to time with the latest nixpgks/grass package . I can prepare a PR for that.

To wrap-up, there is nothing wrong in this PR and it can be merged as is.

[neteler]

Looks "harmless" to me, more I cannot judge.

[imincik]

Packaging update PR is created in #5671 .