upgrade to support dbt-core v1.6.0

[dataders]

Background

Minor version v1.6 is targeted for final release on July 27, 2023. As a maintainer of a dbt adapter, we strongly encourage you to release a corresponding minor version increment to ensure users of your adapter can make use of this new minor version.

How to upgrade

dbt-labs/dbt-core#7958 is an open discussion with more detailed information. If you have questions, please put them there!

The above linked guide has more information, but below is a high-level checklist of work that would enable a successful 1.6.0 release of your adapter:

### Tasks
- [ ] SUPPORT: materialized views
- [ ] SUPPORT: new `clone` command
- [ ] BEHIND THE SCENES: Drop support for Python 3.7 (if you haven't already)
- [ ] BEHIND THE SCENES: new arg for `adapter.execute()`
- [ ] BEHIND THE SCENES: ensure support for revamped `dbt debug``
- [ ] BEHIND THE SCENES: Add support for new/modified relevant tests

the next minor release: 1.7.0

FYI, dbt-core==1.7.0 is expected to be released on October 12, 2023 in time for Coalesce, the annual analytics engineering conference!

[niteshy]

Fixed by #148