WARN Issues with latest peer dependency postcss-load-config@6 found

[delight]

Describe the bug
A major version of postcss-load-config (6.0.0) got released.
This is not included in the allowed versions of peerDependencies yet

Logs
 WARN  Issues with peer dependencies found
.
└─┬ svelte-check 3.8.0
└─┬ svelte-preprocess 5.1.4
└── ✕ unmet peer postcss-load-config@"^2.1.0 || ^3.0.0 || ^4.0.0 || ^5.0.0": found 6.0.0

To Reproduce
update svelte project dependencies to latest versions

Expected behavior
No warning on updates

Information about your project:

new sveltekit project

• Your operating system: (e.x. OS X 10, Ubuntu Linux 19.10, Windows XP, etc)
  (x)buntu 22.04

• svelte-preprocess version (Please check you can reproduce the issue with the latest release!)
  5.1.4

• Whether your project uses Webpack or Rollup
  vite

I got the simple patch ready

[dummdidumm]

Closed as part of #640