Update example package

Author: janniks

example/package.json

@@ -11,7 +11,8 @@
   "dependencies": {
     "core-js": "^3.6.5",
     "nuxt": "^2.14.12",
-    "prismjs": "^1.22.0"
+    "prismjs": "^1.22.0",
+    "vue-katex": "^0.5.0"
   },
   "devDependencies": {
     "vue-notion": "^1.2.0"