chore(package.json): remove @types/next in dependencies

related: #8

Author: stegano

package-lock.json

@@ -15,7 +15,6 @@
   "dependencies": {
     "@types/http-proxy": "1.17.3",
     "@types/jest": "^25.1.3",
-    "@types/next": "^9.0.0",
     "http-proxy": "^1.18.0",
     "jest": "^25.1.0",
     "rollup": "^1.31.1",