chore: add playground

Author: danielroe

package.json

@@ -59,9 +59,6 @@
   "resolutions": {
     "@nuxtjs/html-validator": "link:./"
   },
-  "volta": {
-    "node": "18.14.2"
-  },
   "publishConfig": {
     "access": "public"
   },

playground/package.json

@@ -1,3 +1,7 @@
 {
-  "name": "html-validator-playground"
+  "name": "html-validator-playground",
+  "dependencies": {
+    "@nuxtjs/html-validator": "latest",
+    "nuxt": "latest"
+  }
 }