build(deps): update vuex requirement from 3.1.0 to 3.1.1

Updates the requirements on [vuex](https://github.com/vuejs/vuex) to permit the latest version.
- [Release notes](https://github.com/vuejs/vuex/releases)
- [Commits](https://github.com/vuejs/vuex/compare/v3.1.0...v3.1.1)

package.json

@@ -67,7 +67,7 @@
     "vue-router": "3.0.2",
     "vue-splitpane": "1.0.4",
     "vuedraggable": "2.20.0",
-    "vuex": "3.1.0",
+    "vuex": "3.1.1",
     "xlsx": "0.14.1"
   },
   "devDependencies": {