Wondering this as well

I just did the following to resolve my problems:

1. Fork the package to my Github.
2. Change up the composer.json file so that the requirement for Laravel is ~5.
3. Publish the forked package on Pakagist.
4. Install the custom published packaged via composer.

I know it's not the best way to do it, but it's the only way I can see that works.

Please don't do that. You are just filling Packagist with useless packages. Packagist even warns you about this. Only submit your forks if the original one is abandoned and you are going to maintain it for a long time.

Note that you should not rename the package unless you really intend to fork it in the long term, and completely move away from the original package. Composer will correctly pick your package over the original one since the custom repository has priority over packagist.

You should fork the package and then require your fork, directly in your composer.json. See the docs: https://getcomposer.org/doc/05-repositories.md#vcs

Oh, I had no idea. I'll make sure to clean this up.