Update eslint and eslint-plugin-vue to the latest version (#935)

* Update eslint to version 6.0.1
* Update eslint-plugin-vue to version 5.2.3
* Update lockfile package-lock.json

Co-authored-by: Flo Edelmann <florian-edelmann@online.de>

Author: greenkeeper[bot]

package-lock.json

@@ -60,11 +60,11 @@
     "diff": "^4.0.1",
     "dir-compare": "^1.7.1",
     "disparity": "^2.0.0",
-    "eslint": "^5.13.0",
+    "eslint": "^6.0.1",
     "eslint-plugin-json": "^1.3.2",
     "eslint-plugin-promise": "^4.0.1",
     "eslint-plugin-security": "^1.4.0",
-    "eslint-plugin-vue": "^5.2.1",
+    "eslint-plugin-vue": "^5.2.3",
     "husky": "^2.0.0",
     "jsdoc-to-markdown": "^5.0.0",
     "libxmljs": "^0.19.5",