fix: Include django_lifecycle_checks in build

Author: EnriqueSoria

setup.py

@@ -48,7 +48,7 @@ def readme():
     description="Declarative model lifecycle hooks.",
     author=get_metadata("django_lifecycle", "author"),
     author_email=get_metadata("django_lifecycle", "author_email"),
-    packages=["django_lifecycle"],
+    packages=["django_lifecycle", "django_lifecycle_checks"],
     url="https://github.com/rsinger86/django-lifecycle",
     project_urls={
         "Documentation": "https://rsinger86.github.io/django-lifecycle/",