Moved pool tests to require-dev where it should be

Author: WyriHaximus

composer.json

@@ -14,7 +14,6 @@
         "ext-parallel": "*",
         "react-parallel/contracts": "^1.0",
         "react-parallel/event-loop": "^1.0",
-        "react-parallel/pool-tests": "^3.0",
         "react-parallel/runtime": "^2.0",
         "react/event-loop": "^1.1",
         "react/promise": "^2.7",
@@ -25,6 +24,7 @@
     "require-dev": {
         "bruli/php-value-objects": "^2.0",
         "moneyphp/money": "^3.2 || ^3.2.1",
+        "react-parallel/pool-tests": "^3.0",
         "wyrihaximus/async-test-utilities": "^3.2",
         "wyrihaximus/iterator-or-array-to-array": "^1.1"
     },