pg_ivm 1.5 released

IVM Development Group is pleased to announce the release of [pg_ivm 1.5]( https://github.com/sraoss/pg_ivm/releases/tag/v1.5 ).

Changes since the v1.4 release include:

### New feature

* Add CTE support (Yugo Nagata)

Simple CTEs (WITH queries) which do not contain aggregates or DISTINCT are supported similarly to simple sub-queries.

### Bug fixes

* Fix automatic index creation on views containing a subquery (Yugo Nagata)

Previously, a unique index could not be created properly when an IMMV containing a subquery was created even if all primary key attributes appeared in the target list.

* Fix to allow generate_series in FROM clause (Yugo Nagata)

Using generate_series caused an error due to an ambiguous reference at the maintenance time because this function is used internally.

* Prohibit to create IMMVs using subqueries in a function argument or in an expression (Yugo Nagata)

For example, views like

- `SELECT ... FROM func(..., (SELECT ... FROM ...), ..) ...;`
- `SELECT expr(SELECT ... FROM ...) FROM ...;`

cannot be maintained correctly, so they are prohibited.

**Full Changelog**: https://github.com/sraoss/pg_ivm/compare/1.4...v1.5

### About pg_ivm

pg_ivm is an extension module that provides Incremental View Maintenance (IVM) feature.

Incremental View Maintenance (IVM) is a way to make materialized views up-to-date in
which only incremental changes are computed and applied on views rather than recomputing.
pg_ivm provides a kind of immediate maintenance, in which materialized views are updated
immediately after a base table is modified.

Source repository: [https://github.com/sraoss/pg_ivm](https://github.com/sraoss/pg_ivm)