Little update + fanmade french translation

The game updates to version 0.3.1. I've made this update mainly to solve a lot of the compatibility issues(fatal error when the game boots up, the game not running at correct FPS, controller not recognized, etc. etc.), but I also made some small modifications:

• Finally added the credits (a very rough version, it will be updated in the next version)
• Balanced some things (in particular, some upgrades have been buffed)
• Changed the Moon's shop prices a bit 

And finally, a fanmade French translation of this update was made by Seoku (https://se0ku.itch.io/). You can download the patch here: https://se0ku.itch.io/no-skin-fr. Thank you Seoku for this huge work!