Could not find a matching version of package flarum/gdpr. Check the package spelling, your version constraint and that the package is available in a stability which matches your minimum-stability (beta).
composer.json:
GNU nano 8.1 composer.json
{
"name": "flarum/flarum",
"description": "Delightfully simple forum software.",
"type": "project",
"keywords": [
"forum",
"discussion"
],
"minimum-stability": "beta",
"prefer-stable": true,
"homepage": "https://flarum.org/",
"license": "MIT",
"authors": [