Update dependency eslint to v7

Author: briancaffey

quasar/package.json

@@ -34,7 +34,7 @@
     "@quasar/app": "1.9.0",
     "@vue/eslint-config-prettier": "6.0.0",
     "babel-eslint": "10.1.0",
-    "eslint": "5.16.0",
+    "eslint": "7.12.0",
     "eslint-loader": "4.0.2",
     "eslint-plugin-prettier": "3.1.3",
     "eslint-plugin-vue": "6.2.2"