deps: remove postcss-import

Author: Michael Smith

package-lock.json

@@ -55,7 +55,6 @@
     "github-slugger": "^2.0.0",
     "lodash.debounce": "4.0.8",
     "postcss": "^8.4.49",
-    "postcss-import": "^16.1.0",
     "postcss-preset-env": "^11.1.1",
     "prism-react-renderer": "^2.3.1",
     "prismjs": "^1.30.0",