Velocita is a caching reverse proxy for Composer repositories and package distribution locations, such as Packagist or GitHub.
Install composer-velocita and point it to https://velocita.viosys.de/:
composer global config allow-plugins.gmta/composer-velocita true
composer global require gmta/composer-velocita
composer velocita:enable https://velocita.viosys.de/
Mirrors for the following locations are configured and active: