Update husky integration code for husky v1.0.0 (#5266)

Latest husky (version 1.0.0) moved its hooks config from the `scripts` field to a new `husky` field in `package.json` ([ChangeLog](https://github.com/typicode/husky/blob/master/CHANGELOG.md)).

The `scripts` syntax described here, although shorter, will be deprecated soon. This change replaces it with the new husky syntax.

The new syntax is already used in [precommit.md](https://github.com/prettier/prettier/blob/master/docs/precommit.md).

website/pages/en/index.js

@@ -298,11 +298,13 @@ class GetStartedSection extends React.Component {
                       {bash`npm install pretty-quick husky --save-dev`}
                     </MarkdownBlock>
                   </div>
-                  Then edit <code>package.json</code>:
+                  Then add this config to <code>package.json</code>:
                   <MarkdownBlock>
                     {json({
-                      scripts: {
-                        precommit: "pretty-quick --staged"
+                      husky: {
+                        hooks: {
+                          "pre-commit": "pretty-quick --staged"
+                        }
                       }
                     })}
                   </MarkdownBlock>