Update README.md

Author: danieledep

README.md

@@ -12,10 +12,10 @@ demo: [https://danieledep.github.io/rovers-dithering-playground/](https://daniel
 Download your own [NASA API key](https://api.nasa.gov/) and enter it in:  `src/NasaApiKey.js`  
 Run in your terminal:
 
-``
+```
 npm run build      
 npm run dev
-``
+```
 
 
 ## Credits