After looking for a solution for a while, I finally found out how to change the FoV, and it is so simple!

To change your FoV, you need to download the following program:
Flawlesswidescreen

Due to the Steam filter, I cannot link the program directly, but if you use Google, it will be your first hit! This program can also be used for many other games.

Step 1
Download the program, and when the download is complete, start both the program and the game.

Step 2
Type "Singularity" into the search box of the program, then click on it. The program will install the plug-in, and when that is done, you will see a screen. This screen shows you all the different options you have. On the first page, you can change the resolution of the game, but what you want is on the second page. Voilà! There it is, the FoV changer. Adjust it as you wish, and it will automatically apply to your game. Have fun!


Reminder: This guide is intended to save you time. Instead of spending time searching Google for a solution and encountering posts claiming it's impossible, you can follow these simple steps and start enjoying the game right away.

Update, 2020-01-12:
Check the comments for other ways to change the FoV, in case you would like to try them out.