fix: correctly handle injecting environment variables to deployment tasks

Also test that release tasks are invoked the correct environment.

Closes #3817

tests/apps/dockerfile-release/project/settings/__init__.py

@@ -0,0 +1,12 @@
+import os
+
+environment = os.getenv('ENVIRONMENT')
+
+if environment == 'dev':
+    from .dev import *
+elif environment == 'staging':
+    from .staging import *
+elif environment == 'production':
+    from .staging import *
+else:
+    raise Exception("Invalid environment")