chore: add root prop to .eslintrc (#11914)

**Motivation**

Currently, ESlint crashes when someone has bundled react-navigation as a
submodule to the project (here, in react-native-screens we've got one 😁
). Our goal is to mark react-navigation's ESlint RC file as a root
configuration, to omit configuration mismatching.

.eslintrc.json

@@ -1,4 +1,5 @@
 {
+  "root": true,
   "extends": "satya164",
   "plugins": ["simple-import-sort"],
   "settings": {