Finding dependencies of materialized views

Hi there.

The v_view_dependency script:
https://github.com/awslabs/amazon-redshift-utils/blob/master/src/AdminViews/v_view_dependency.sql#L1
does not work for materialized views.

I had a table that would not drop without 'cascade'. I could not find a dependency via the view. Dropping the table I discovered a materialized view was dropped.
It would be useful if we could use the `v_view_dependency` view for materialized views.

thanks

Start with src/AdminViews/v_view_dependency.sql and reproduce the reported case where dropping a table also drops a materialized view. Review how the view finds dependencies, then verify that materialized-view dependencies appear in its results and that the original table can be identified before a cascade drop.

Written by the indexing model from the issue text.