Revert #208 (#214)

It looks like Node v18 or v20 isn't viable. Talk about testing in
production.

Author: CountBleck

package-lock.json

@@ -16,7 +16,7 @@
     "node-fetch": "^2.6.7",
     "pngquant": "^4.0.0",
     "prism-themes": "^1.9.0",
-    "sharp": "^0.32.6",
+    "sharp": "^0.30.7",
     "vuepress": "^1.9.7",
     "vuepress-plugin-serve": "^2.0.4",
     "vuepress-plugin-sitemap": "^2.3.1"