### What problem does this PR solve?

Fix typo in README.md

Issue link:

### What is changed and how it works?

### Code changes

- [ ] Has Code change
- [ ] Has CI related scripts change

### Check List

Tests <!-- At least one of them must be included. -->

- [ ] Unit test
- [ ] Integration test
- [ ] Manual test (knn performance test)
- [x] No code

Side effects

- [ ] Performance regression: Consumes more CPU
- [ ] Performance regression: Consumes more Memory
- [ ] Breaking backward compatibility

### Note for reviewer