Update dependency doctrine/orm to v3

Author: renovate[bot]

composer.json

@@ -12,7 +12,7 @@
         "doctrine/annotations": "^1.0",
         "doctrine/doctrine-bundle": "^2.5",
         "doctrine/doctrine-migrations-bundle": "^3.2",
-        "doctrine/orm": "^2.10",
+        "doctrine/orm": "^3.0",
         "guzzlehttp/guzzle": "^7.4",
         "guzzlehttp/oauth-subscriber": "^0.8.1",
         "nelmio/cors-bundle": "^2.2",