flake: update everything (#137)

New state:

Last modified: 2025-01-08 15:30:35
Inputs:
├───flake-utils:
github:numtide/flake-utils/11707dc2f618dd54ca8739b309ec4fc024de578b
│   Last modified: 2024-11-13 13:27:16
│ └───systems:
github:nix-systems/default/da67096a3b9bf56a91d16901293e51ba5b49a27e
│       Last modified: 2023-04-09 01:27:08
├───nixpkgs:
github:nixos/nixpkgs/8f3e1f807051e32d8c95cd12b9b421623850a34d
│   Last modified: 2025-01-04 09:41:09
└───pre-commit-hooks:
github:cachix/pre-commit-hooks.nix/a5a961387e75ae44cc20f0a57ae463da5e959656
    Last modified: 2025-01-02 21:37:24
├───flake-compat:
github:edolstra/flake-compat/0f9255e01c2351cc7d116c072cb317785dd33b33
    │   Last modified: 2023-10-04 06:37:54
├───gitignore:
github:hercules-ci/gitignore.nix/637db329424fd7e46cf4185293b9cc8c88c95394
    │   Last modified: 2024-02-27 18:28:52
    │   └───nixpkgs follows input 'pre-commit-hooks/nixpkgs'
    └───nixpkgs follows input 'nixpkgs'

Before submitting your PR, check that you've:

- [x] Documented new APIs with [Haddock
markup](https://www.haskell.org/haddock/doc/html/index.html)
- [x] Added [`@since`
declarations](http://haskell-haddock.readthedocs.io/en/latest/markup.html#since)
to the Haddock

After submitting your PR:

- [ ] Update the Changelog.md file with a link to your PR
  N/A
- [ ] Bumped the version number if there isn't an `(unreleased)` on the
Changelog
  N/A
- [ ] Check that CI passes (or if it fails, for reasons unrelated to
your change, like CI timeouts)
  N/A I think, but nix flake check passes

<!---Thanks so much for contributing! :)

_If these checkboxes don't apply to your PR, you can delete them_-->

flake.nix

@@ -7,7 +7,6 @@
     pre-commit-hooks = {
       url = "github:cachix/pre-commit-hooks.nix";
       inputs.nixpkgs.follows = "nixpkgs";
-      inputs.flake-utils.follows = "flake-utils";
     };
   };
 
@@ -17,7 +16,7 @@
 
   outputs = { self, nixpkgs, flake-utils, pre-commit-hooks }:
     let
-      ghcVer = "ghc948";
+      ghcVer = "ghc96";
       makeHaskellOverlay = overlay: final: prev: {
         haskell = prev.haskell // {
           packages = prev.haskell.packages // {