* Bumped Spilo image tag to the one that supports PostgreSQL 15. Using CDP version temporarily until non-CDP one is released.
* Added support for PostgreSQL 15 and made it default. 9.5 and 9.6 are now no longer supported
* Bumped spilo image tag to 2.1-p9
* Bumped spilo image in test launcher
Co-authored-by: yoshihiko <ariyoshi10@gmail.com>
Co-authored-by: Felix Kunde <felix-kunde@gmx.de>