bump vitepress + list vue in deps

Author: yyx990803

package.json

@@ -7,9 +7,10 @@
   "devDependencies": {
     "@types/node": "^16.9.1",
     "cheap-watch": "^1.0.3",
-    "vitepress": "^0.20.0"
+    "vitepress": "^0.20.1"
   },
   "dependencies": {
+    "vue": "^3.2.21",
     "@vue/repl": "^0.4.3",
     "@vue/theme": "^0.1.13"
   }