Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires illuminate/collections dev-8.x, found illuminate/collections[dev-master, v8.0.0, ..., 8.x-dev, v9.0.0-beta.1, ..., 9.x-dev, 10.x-dev (alias of dev-master)] but it does not match the constraint.