fix(readme): use correct instructions to install React bindings (#455)

The package is now `@fluent/react` and the instructions pointed to the old package name

Author: erickwilder

README.md

@@ -27,9 +27,8 @@ be installed independently of each other.
   - [@fluent/sequence](https://github.com/projectfluent/fluent.js/tree/master/fluent-sequence)
   - [@fluent/syntax](https://github.com/projectfluent/fluent.js/tree/master/fluent-syntax)
 
-You can install each of the above packages via `npm`, e.g. `npm install
-fluent-react`.  See the end of this `README` for instructions on how to build
-`fluent.js` locally.
+You can install each of the above packages via `npm`, e.g. `npm install @fluent/react`.  
+See the end of this `README` for instructions on how to build `fluent.js` locally.
 
 
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