[chore] flake.lock: update inputs

Fix for OpenSSH vulnerability:

```
• Updated input 'home-manager':
    'github:nix-community/home-manager/a1fddf0967c33754271761d91a3d921772b30d0e' (2024-06-16)
  → 'github:nix-community/home-manager/391ca6e950c2525b4f853cbe29922452c14eda82' (2024-07-01)
• Updated input 'nixos-hardware':
    'github:NixOS/nixos-hardware/a59f00f5ac65b19382617ba00f360f8bc07ed3ac' (2024-06-29)
  → 'github:NixOS/nixos-hardware/6e253f12b1009053eff5344be5e835f604bb64cd' (2024-07-02)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/89c49874fb15f4124bf71ca5f42a04f2ee5825fd' (2024-06-26)
  → 'github:NixOS/nixpkgs/d032c1a6dfad4eedec7e35e91986becc699d7d69' (2024-07-01)
• Updated input 'nixvim':
    'github:nix-community/nixvim/c062b976eff9f13597c7c23d77a6b3ac677b7fd5' (2024-06-29)
  → 'github:nix-community/nixvim/079c2c479b5707adf0b03f817be30945c92c15cf' (2024-07-01)
• Updated input 'nixvim/flake-parts':
    'github:hercules-ci/flake-parts/2a55567fcf15b1b1c7ed712a2c6fadaec7412ea8' (2024-06-01)
  → 'github:hercules-ci/flake-parts/c3c5ecc05edc7dafba779c6c1a61cd08ac6583e9' (2024-06-30)
• Updated input 'nixvim/treefmt-nix':
    'github:numtide/treefmt-nix/065a23edceff48f948816b795ea8cc6c0dee7cdf' (2024-06-24)
  → 'github:numtide/treefmt-nix/8df5ff62195d4e67e2264df0b7f5e8c9995fd0bd' (2024-06-30)
• Updated input 'unstable':
    'github:NixOS/nixpkgs/b2852eb9365c6de48ffb0dc2c9562591f652242a' (2024-06-27)
  → 'github:NixOS/nixpkgs/2741b4b489b55df32afac57bc4bfd220e8bf617e' (2024-06-29)
```

nvim/standalone.nix

@@ -2,7 +2,6 @@
   imports = [./options.nix ./plugins.nix ./mappings.nix ./augroups.nix];
 
   config = {
-    package = pkgs.unstable.neovim-unwrapped;
     globals.mapleader = " ";
     # Appearance
     colorschemes.gruvbox = {