Add tests directory to default PSR-4 autoloader

This way it is available in integration tests within a Magento installation without changes in the root composer.json

Author: schmengler

composer.json

@@ -27,14 +27,10 @@
       "src/registration.php"
     ],
     "psr-4": {
+      "IntegerNet\\SessionUnblocker\\Test\\": "tests/",
       "IntegerNet\\SessionUnblocker\\": "src/"
     }
   },
-  "autoload-dev": {
-    "psr-4": {
-      "IntegerNet\\SessionUnblocker\\Test\\": "tests/"
-    }
-  },
   "repositories": [
     {
       "type": "composer",