add generic ASGI entry point, for uvicorn etc.

{{ cookiecutter.repo_name }}/{{ cookiecutter.package_name }}/web/app.py

@@ -33,3 +33,10 @@ def make_wsgi_app():
     Make and return the WSGI app (generic entry point).
     """
     return base.make_wsgi_app(main)
+
+
+def make_asgi_app():
+    """
+    Make and return the ASGI app.
+    """
+    return base.make_asgi_app(main)