Bump vuex from 3.1.3 to 3.4.0

Bumps [vuex](https://github.com/vuejs/vuex) from 3.1.3 to 3.4.0.
- [Release notes](https://github.com/vuejs/vuex/releases)
- [Changelog](https://github.com/vuejs/vuex/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vuex/compare/v3.1.3...v3.4.0)

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

package.json

@@ -61,7 +61,7 @@
     "vue-router": "^3.1.6",
     "vue-server-renderer": "^2.6.11",
     "vue-template-compiler": "^2.6.11",
-    "vuex": "^3.1.3",
+    "vuex": "^3.4.0",
     "vuex-router-sync": "^5.0.0",
     "webpack": "^4.42.0",
     "webpack-cli": "^3.3.11",