chore: upgrade vuepress (#3274)

Author: posva

docs/.vuepress/config.js

@@ -1,4 +1,4 @@
-module.exports = {
+module.exports = ctx => ({
   locales: {
     '/': {
       lang: 'en-US',
@@ -53,15 +53,26 @@ module.exports = {
       }
     ]
   ],
-  serviceWorker: true,
-  theme: 'vue',
+  theme: '@vuepress/vue',
+  plugins: [
+    [
+      '@vuepress/pwa',
+      {
+        serviceWorker: true,
+        updatePopup: true
+      }
+    ]
+  ],
   themeConfig: {
-    algolia: {
-      apiKey: 'f854bb46d3de7eeb921a3b9173bd0d4c',
-      indexName: 'vue-router'
-    },
+    algolia: ctx.isProd
+      ? {
+          apiKey: 'f854bb46d3de7eeb921a3b9173bd0d4c',
+          indexName: 'vue-router'
+        }
+      : null,
     repo: 'vuejs/vue-router',
     docsDir: 'docs',
+    smoothScroll: true,
     locales: {
       '/': {
         label: 'English',
@@ -366,4 +377,4 @@ module.exports = {
       }
     }
   }
-}
+})

docs/.vuepress/style.styl renamed to docs/.vuepress/styles/index.styl

@@ -59,6 +59,8 @@
     ]
   },
   "devDependencies": {
+    "@vuepress/plugin-pwa": "^1.5.3",
+    "@vuepress/theme-vue": "^1.5.3",
     "axios": "^0.19.0",
     "babel-core": "^6.24.1",
     "babel-eslint": "^10.0.2",
@@ -97,10 +99,10 @@
     "selenium-server": "^3.141.59",
     "terser": "^4.2.0",
     "typescript": "^3.5.2",
-    "vue": "^2.5.16",
-    "vue-loader": "^15.2.1",
-    "vue-template-compiler": "^2.5.16",
-    "vuepress": "^0.14.11",
+    "vue": "^2.6.11",
+    "vue-loader": "^15.9.3",
+    "vue-template-compiler": "^2.6.11",
+    "vuepress": "^1.5.3",
     "vuepress-theme-vue": "^1.1.1",
     "webpack": "^4.35.2",
     "webpack-dev-middleware": "^3.7.0",