Minimal stability problem

I want to install neitanod/forceutf8

via composer and I get the error:

Couldn't find package in any version for your minimum stability (dev). Check the package for correct spelling or minimum stability.

This is the second time he has done this - previously with html2text

. How to fix it?

Edit: My composer .json:

{
  "name": "vendor_name/package_name",
  "description": "description_text",
  "minimum-stability": "dev",
  "license": "proprietary",
  "authors": [
    {
      "name": "author name",
      "email": "email@example.com"
    }
  ],
  "require": {
    ...
  }
}