typo:Update README.md

[jiangzhx]

Description

Motivation and Context

How Has This Been Tested?

Types of Changes

• [x] Bug fix (non-breaking change that fixes an issue)
• [ ] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] Code follows the code style of this project.
• [x] Change requires a change to the documentation.
• [x] I have updated the documentation accordingly.