docs(installation): fix instructions for cjs (#83)

Without using `withDevTools(AppExport)`, Remix throws a warning:
```
Warning: Functions are not valid as a React child. This may happen if you return a Component instead of <Component /> from render. Or maybe you meant to call this function rather than return it.
```

Author: obviyus

README.md

@@ -69,7 +69,7 @@ If you're using CJS instead of ESM you can do the following instead:
 if(process.env.NODE_ENV === 'development') { 
 - const { withDevTools } = await import("remix-development-tools"); 
 + const { withDevTools } = require("remix-development-tools"); 
-  AppExport = withDevTools
+  AppExport = withDevTools(AppExport);
 }
 export default AppExport;