Fixed bug where default env were overriding custom env vars (#154)

Author: Nusnus

src/pytest_celery/vendors/worker/container.py

@@ -71,7 +71,7 @@ def buildargs(cls) -> dict:
     @classmethod
     def env(cls, celery_worker_cluster_config: dict, initial: dict | None = None) -> dict:
         env = initial or {}
-        env = {**env, **DEFAULT_WORKER_ENV.copy()}
+        env = {**DEFAULT_WORKER_ENV.copy(), **env}
 
         config_mappings = [
             ("celery_broker_cluster_config", "CELERY_BROKER_URL"),