Fix typo in README.md

[mchisolm0]

Issue: #690

What I did

I replaced a semi-colon with a comma at the end of the line for the setup section.

From the README.md file

Reanimated setup
Make sure you have react-native-reanimated in your project and the plugin setup in your babel config.

// babel.config.js
plugins: ['react-native-reanimated/plugin']; // <---- This line

How to test

No tests are needed.

If your answer is yes to any of these, please make sure to include it in your PR.

[dannyhw]

thanks!