minor #82 Allow Contracts v2 (fabpot)

This PR was merged into the master branch.

Discussion
----------

Allow Contracts v2

/cc @nicolas-grekas @weaverryan

Commits
-------

aee0de0 Allow Contracts v2

Author: fabpot

composer.json

@@ -26,7 +26,7 @@
         "symfony/config": "^3.4 || ^4.0 || ^5.0",
         "symfony/dependency-injection": "^3.4 || ^4.0 || ^5.0",
         "symfony/http-kernel": "^3.4 || ^4.0 || ^5.0",
-        "symfony/service-contracts": "^1.0"
+        "symfony/service-contracts": "^1.0 || ^2.0"
     },
     "require-dev": {
         "symfony/framework-bundle": "^3.4 || ^4.0 || ^5.0",