Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires flarum/core ^2.0.0, found flarum/core[dev-release/v1.6.2, dev-release/v1.6.3, dev-release/v1.7.2, dev-main-borked-with-split-conflicts, dev-main, dev-master, v0.1.0-beta, ..., v0.1.0-beta.16, v1.0.0, ..., 1.x-dev (alias of dev-master)] but it does not match the constraint. Problem 2 - Root composer.json requires flarum/testing ^2.0.0, found flarum/testing[dev-main, dev-master, dev-as/rollback-extension-migrations-before-tests, dev-as/include-current-extension, dev-as/start-transaction-before-boot, v0.1.0-beta.1, v0.1.0-beta.16, v0.1.0-beta.16.1, v1.0.0, ..., 1.x-dev (alias of dev-master)] but it does not match the constraint. Problem 3 - Root composer.json requires flarum/nicknames ^2.0.0, found flarum/nicknames[dev-main, dev-master, v0.1.0-beta.15, v0.1.0-beta.16, 0.1.0-beta.16.1, v1.0.0, ..., 1.x-dev (alias of dev-master)] but it does not match the constraint.