add vue-template-compiler to devDependencies (#654)

Author: flier

package.json

@@ -18,6 +18,7 @@
   "license": "ISC",
   "devDependencies": {
     "@vuepress/plugin-back-to-top": "^1.9.5",
+    "vue-template-compiler": "^2.7.16",
     "vuepress": "^1.9.5",
     "vuepress-plugin-code-copy": "^1.0.6",
     "vuepress-plugin-seo": "^0.2.0",