update depdency: vuepress

{

  "devDependencies": {

    "@vuepress/plugin-docsearch": "2.0.0-beta.48",

    "@vuepress/plugin-git": "2.0.0-beta.48",

    "@vuepress/plugin-google-analytics": "2.0.0-beta.48",

    "@vuepress/plugin-medium-zoom": "2.0.0-beta.48",

    "@vuepress/plugin-nprogress": "2.0.0-beta.48",

    "@vuepress/plugin-pwa": "2.0.0-beta.48",

    "@vuepress/plugin-pwa-popup": "2.0.0-beta.48",

    "@vuepress/plugin-register-components": "2.0.0-beta.48",

    "@vuepress/plugin-toc": "2.0.0-beta.48",

    "vuepress": "2.0.0-beta.48",

    "vuepress-plugin-sitemap2": "^2.0.0-beta.83"

    "@vuepress/plugin-docsearch": "2.0.0-beta.49",

    "@vuepress/plugin-git": "2.0.0-beta.49",

    "@vuepress/plugin-google-analytics": "2.0.0-beta.49",

    "@vuepress/plugin-medium-zoom": "2.0.0-beta.49",

    "@vuepress/plugin-nprogress": "2.0.0-beta.49",

    "@vuepress/plugin-pwa": "2.0.0-beta.49",

    "@vuepress/plugin-pwa-popup": "2.0.0-beta.49",

    "@vuepress/plugin-register-components": "2.0.0-beta.49",

    "@vuepress/plugin-toc": "2.0.0-beta.49",

    "vuepress": "2.0.0-beta.49",

    "vuepress-plugin-sitemap2": "^2.0.0-beta.86"

  },

  "scripts": {

    "docs:dev": "vuepress dev docs",