warning An error was encountered in plugin "sitemap"

[apgapg]

  plugins: [
    "@vuepress/plugin-back-to-top",
    "@vuepress/plugin-medium-zoom",
    [
      "sitemap",
      {
        hostname: "https://apgapg.github.io/vuepress-diary/",
      },
    ],
  ],

sitemap is not generated. Am I missing something?

package.json

{
  "name": "vuepress-diary",
  "version": "0.0.1",
  "description": "Official Vuepress diary of Ayush P Gupta",
  "main": "index.js",
  "authors": {
    "name": "Ayush P Gupta",
    "email": "ayushpguptaapg@gmail.com"
  },
  "repository": "/vuepress-diary",
  "scripts": {
    "dev": "vuepress dev src",
    "build": "vuepress build src"
  },
  "license": "MIT",
  "devDependencies": {
    "vuepress": "^1.5.3"
  }
}

[apgapg]

My Bad

I was not adding -D flag as mentioned in docs

For eg. Correct way is to use dev_dependency:

npm install -D @vuepress/plugin-medium-zoom