indexes in a table.

Currently the pg_class catalog is filtered out to retrieve the indexes in a
table by its relkind value. Which in versions lower than 11 of PostgreSQL
is always `i` (lower case). But since version 11, PostgreSQL
supports partitioned indexes referenced with a relkind value of `I`
(upper case). This makes any feature within the current code base to exclude those
partitioned indexes.

The solution proposed is to make use of the `IN` clause to filter those
relkind values of `i` and/or `I` when retrieving a table indexes.