chore(package): update vue-i18n to version 7.6.0

Closes #996

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "vue": "^2.5.13",
     "vue-checkbox-radio": "^0.6.0",
     "vue-directive-tooltip": "^1.4.2",
-    "vue-i18n": "^5.0.2",
+    "vue-i18n": "^7.6.0",
     "vue-js-toggle-button": "^1.2.2",
     "vue-notification": "^1.3.6",
     "vue-resource": "^1.3.6",