Install cross-env as normal dependency as it is needed also in production

Author: vejol

src/content/4/en/part4b.md

@@ -42,10 +42,10 @@ Next, let's change the scripts in our notes application <i>package.json</i> file
 
 We specified the mode of the application to be <i>development</i> in the _npm run dev_ script. We also specified that the default _npm start_ command will define the mode as <i>production</i>.
 
-There is a slight issue in the way that we have specified the mode of the application in our scripts: it will not work on Windows. We can correct this by installing the [cross-env](https://www.npmjs.com/package/cross-env) package as a development dependency with the command:
+There is a slight issue in the way that we have specified the mode of the application in our scripts: it will not work on Windows. We can correct this by installing the [cross-env](https://www.npmjs.com/package/cross-env) package as a project dependency using the command:
 
 ```bash
-npm install --save-dev cross-env
+npm install cross-env
 ```
 
 We can then achieve cross-platform compatibility by using the cross-env library in our npm scripts defined in <i>package.json</i>:

src/content/4/fi/osa4b.md

@@ -40,7 +40,7 @@ Määritellään nyt tiedostossa <i>package.json</i>, että testejä suoritettae
 
 Samalla määriteltiin, että suoritettaessa sovellusta komennolla _npm run dev_ sovelluksen moodi on <i>development</i>. Jos sovellusta suoritetaan komennolla _npm start_, on moodiksi määritelty <i>production</i>.
 
-Määrittelyssämme on kuitenkin pieni ongelma: se ei toimi Windowsilla. Tilanne korjautuu asentamalla kirjasto [cross-env](https://www.npmjs.com/package/cross-env) komennolla
+Määrittelyssämme on kuitenkin pieni ongelma: se ei toimi Windowsilla. Tilanne korjautuu asentamalla kirjasto [cross-env](https://www.npmjs.com/package/cross-env) projektin riippuvuudeksi komennolla
 
 ```bash
 npm install cross-env