Test PostgreSQL adapter with multiple versions and at least with the version of PostgreSQL on SAP BTP, Hyperscaler Option

[gregorwolf]

Based on the documentation page for Parameters for the PostgreSQL on SAP BTP, Hyperscaler Option, the latest available version is 14. With #351 the testing was switched to PostgreSQL v16. I would suggest that we should tests at least the latest PostgreSQL version that is supported on BTP plus the versions up to the latest stable release. Currently that would be 14, 15 and 16.

[nils]

Adding to this, I figured out that PostgreSQL 12 (which is very old, I know 🙂) is not fully supported. While it generally works, the output converter for timestamps (YYYY-MM-DD"T"HH24:MI:SS.FF3"Z") silently fails because the "FF3" bit is only supported since PostgreSQL 13 (12 docs vs V13 docs).

So stating the tested and targeted PostgreSQL versions in the @cap-js/postgres documentation might be helpful.