Bump vue-router from 3.5.4 to 3.6.4

Bumps [vue-router](https://github.com/vuejs/router) from 3.5.4 to 3.6.4.
- [Release notes](https://github.com/vuejs/router/releases)
- [Commits](https://github.com/vuejs/router/commits)

---
updated-dependencies:
- dependency-name: vue-router
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -58,7 +58,7 @@
     "vue-easymde": "^2.0.0",
     "vue-infinite-loading": "^2.4.5",
     "vue-material-design-icons": "^5.1.2",
-    "vue-router": "^3.5.4",
+    "vue-router": "^3.6.4",
     "vue-smooth-dnd": "^0.8.1",
     "vuex": "^3.6.2",
     "vuex-router-sync": "^5.0.0"