yarn install updates

Author: Matthew Saginario

docs/installation/installation.md

@@ -387,11 +387,11 @@ include them in the sprockets asset pipeline.
 To add the packages using yarn run these commands:
 
 ```bash
-yarn 'react', '16'
-yarn 'react-dom', '16'
-yarn 'react-router', '^5.0.0'
-yarn 'react-router-dom', '^5.0.0'
-yarn 'react_ujs', '^2.5.0'
+yarn add react@16
+yarn add react-dom@16
+yarn react-router@5.0.0
+yarn react-router-dom@5.0.0
+yarn react_ujs@5.0
 ```
 
 And then add a `cancel_import` directive to the `hyperstack.rb` initializer in your the Rails `config/initializers` directory: