Revert "Update postcss-load-config to version 4.0.1 (#8686)"

This reverts commit c47e666.

Node 12 reached EOL on 30 April 2022 after which there will be no more bugfix or security releases. This is one reason why `postcss-load-config` dropped support for Node 10 *and* 12. However, as we still support Node 12 in Tailwind CSS v3, we can’t upgrade to `postcss-load-config` 4.0.

Author: thecrypticace

package-lock.json

@@ -79,7 +79,7 @@
     "postcss": "^8.4.14",
     "postcss-import": "^14.1.0",
     "postcss-js": "^4.0.0",
-    "postcss-load-config": "^4.0.1",
+    "postcss-load-config": "^3.1.4",
     "postcss-nested": "5.0.6",
     "postcss-selector-parser": "^6.0.10",
     "postcss-value-parser": "^4.2.0",