postgresql: default to v15 in 23.11

[nbdd0121]

Description of changes

Change the default postgres version from 14 to 15 in release 23.11.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[thoughtpolice]

This also needs a change in all-packages.nix to change the default postgresql and postgresqlPackages expressions.

EDIT: Specifically, look here — https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/all-packages.nix#L27276-L27289

Please swap 14 and 15, and make sure the entries are otherwise sorted as they are now.

[natsukium]

This PR should go to staging.
https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#flow-of-merged-pull-requests

[kirillrdy]

@nbdd0121 please rebase and fix merge conflicts

[nbdd0121]

Rebased

[kirillrdy]

@nbdd0121 looks like conflict again

[kirillrdy]

how about making 16 default for 23.11 ?

[nbdd0121]

I think psql 16 is too new for 23.11 release. IIUC timescaledb doesn't yet support psql 16. Probably would be better to wait a bit before making it the default.

[leona-ya]

I'm sorry to come up with this now, i haven't seen this PR before it got merged. I think users will probably get confused that services.postgresql.ensureUsers/ensureDatabases will not "just" work (see #216989 for context). imo we should use postgresql 14 for less confusion (it's okay if you feel different)

[SuperSandro2000]

We have 3 PRs to choose from to fix this: #203474 , #252071, #255961