Cannot install Illuminate/routing because of dependencies

I am trying to add illuminate/routing to my Lumen project but whenever I try to install it through composer, the following error is thrown :

$ composer require illuminate/routing Using version ^5.1 for illuminate/routing ./composer.json has been updated Loading composer repositories with package information Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - The requested package laravel/lumen-framework == 5.0.10.0 could not be found.   Problem 2
    - Installation request for illuminate/contracts == 5.0.33.0 -> satisfiable by illuminate/contracts[v5.0.33].
    - illuminate/routing v5.1.1 requires illuminate/contracts 5.1.* -> satisfiable by illuminate/contracts[v5.1.1].
    - illuminate/routing v5.1.2 requires illuminate/contracts 5.1.* -> satisfiable by illuminate/contracts[v5.1.1].
    - Conclusion: don't install illuminate/contracts v5.1.1
    - Installation request for illuminate/routing ^5.1 -> satisfiable by illuminate/routing[v5.1.1, v5.1.2].

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting    see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

Installation failed, reverting ./composer.json to its original content.
So I have been trying to require contracts, although pretty much the same error was thrown telling me a newer version of illuminate/support is required

Anyways I really don't know what to do anymore, I cant see what my options are.

Here is my composer.json :

{
    "name": "laravel/lumen",
        "description": "The Laravel Lumen Framework.",
        "keywords": ["framework", "laravel", "lumen"],
        "license": "MIT",
        "type": "project",
        "require": {

            "laravel/lumen-framework": "5.1.*",
            "vlucas/phpdotenv": "~1.0",
            "tymon/jwt-auth": "^0.5.4",
        "basicit/lumen-vendor-publish": "^1.0",
        "illuminate/routing": "4"
        },
        "require-dev": {
            "phpunit/phpunit": "~4.0"
        },
        "autoload": {
            "psr-4": {
                "App\\": "app/"
            },
            "classmap": [
                "database/"
                ],
            "files": [
                "app/helpers.php"
                ]
        },
        "autoload-dev": {
            "classmap": [
                "tests/"
                ]
        },
        "config": {
            "minimum-stability": "dev",
            "prefer-stable": true
        }
}

Do you guys have any idea of what I should do ?

Thank you !