Fixed error versions for hyperf/engine. (#7429)

Author: limingxinleo

composer.json

@@ -23,7 +23,7 @@
         "hyperf/contract": "~3.1.0",
         "hyperf/coordinator": "~3.1.0",
         "hyperf/coroutine": "~3.1.0",
-        "hyperf/engine": "~3.1.0",
+        "hyperf/engine": "^2.0",
         "hyperf/pool": "~3.1.0",
         "hyperf/process": "~3.1.0",
         "hyperf/support": "~3.1.0",