Update README.md

[Logrus]

Update documentation.

Description

Update README.md, it contains use of old API which doesn't work and confuses new users.

Checklist

Before creating any Pull Request, confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).

• [x] 📕 I read the Contributing page.
• [x] 🤝 I match the actual coding style.
• [] ✅ I ran flutter analyze without any issues.

Breaking Change

• [ ] 🛠 My feature contain breaking change.

If your feature break something, please detail it