fix(deps): update dependency postcss-load-config to v6

Author: renovate[bot]

packages/eslint-plugin-svelte/package.json

@@ -66,7 +66,7 @@
     "globals": "^16.0.0",
     "known-css-properties": "^0.37.0",
     "postcss": "^8.4.49",
-    "postcss-load-config": "^3.1.4",
+    "postcss-load-config": "^6.0.0",
     "postcss-safe-parser": "^7.0.0",
     "semver": "^7.6.3",
     "svelte-eslint-parser": "^1.4.0"