no warning until we have an upgrade path

Author: rmorshea

src/idom/__main__.py

@@ -1,9 +1,5 @@
-import warnings
-
 from .cli import main
 
 
 if __name__ == "__main__":
-    with warnings.catch_warnings():
-        warnings.simplefilter(DeprecationWarning)
-        main()
+    main()

src/idom/config.py

@@ -66,15 +66,3 @@
 
 For more information on changes to this feature flag see: https://github.com/idom-team/idom/issues/351
 """
-
-if not IDOM_FEATURE_INDEX_AS_DEFAULT_KEY.get():  # pragma: no cover
-    from warnings import warn
-
-    warn(
-        (
-            "In a future release 'IDOM_FEATURE_INDEX_AS_DEFAULT_KEY' will be turned on "
-            "by default. For more information on changes to this feature flag, see: "
-            "https://github.com/idom-team/idom/issues/351"
-        ),
-        DeprecationWarning,
-    )