Bump vuex-persistedstate from 3.2.0 to 4.0.0

Bumps [vuex-persistedstate](https://github.com/robinvdvleuten/vuex-persistedstate) from 3.2.0 to 4.0.0.
- [Release notes](https://github.com/robinvdvleuten/vuex-persistedstate/releases)
- [Changelog](https://github.com/robinvdvleuten/vuex-persistedstate/blob/master/CHANGELOG.md)
- [Commits](https://github.com/robinvdvleuten/vuex-persistedstate/compare/v3.2.0...v4.0.0)

---
updated-dependencies:
- dependency-name: vuex-persistedstate
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -20,7 +20,7 @@
     "nuxt-buefy": "^0.3.31",
     "nuxt-shopify": "^1.10.7",
     "sass-loader": "^10.1.1",
-    "vuex-persistedstate": "^3.2.0"
+    "vuex-persistedstate": "^4.0.0"
   },
   "devDependencies": {
     "@nuxtjs/eslint-config": "^2.0.2",