fix: update vscode settings config of README.md

[rezkiy37]

Summary

The issue (#263) is that there is a little bit deprecated suggestion for VSCode settings config. Once I've added @callstack/eslint-config I saw a warning (check a screenshot below).
Looks like there was an update where autoFix started to be a default value. No sense to set it explicitly anymore. So I've updated README.md.

Test plan

1. Add @callstack/eslint-config to a project
2. Add VSCode config to your .vscode/settings.json

Initial warning

Fix

[thymikee]

Thank you!