chore: replace fs.rmdir with fs.rm

[szymonrybczak]

Summary:

According to Node docs, fs.rmdir(path, { recursive: true }) will be deprecated and right now fs.rm is a right choice.

Test Plan:

1. Clone the repository and do all the required steps from the Contributing guide
2. Run this command:

node /path/to/react-native-cli/packages/cli/build/bin.js clean

Works in the same way as before.

Checklist

• Documentation is up to date to reflect these changes.
• Follows commit message convention described in CONTRIBUTING.md

[thymikee]

Do we want to use force option as well?