update sharp and some audit fixes (#111)

Author: MaxGraey

package-lock.json

@@ -16,7 +16,7 @@
     "node-fetch": "^2.6.1",
     "pngquant": "^4.0.0",
     "prism-themes": "^1.5.0",
-    "sharp": "^0.29.0",
+    "sharp": "^0.29.2",
     "vuepress": "^1.8.2",
     "vuepress-plugin-serve": "^2.0.4",
     "vuepress-plugin-sitemap": "^2.3.1"