Added MIN and MAX aggregations

[eXsio]

• added MIN and MAX aggregations (previously required explicit cast)
• bumped pgrx to 0.17.0

Tests pass for PG 14, 15, 16, 17 and 18.

[pksunkara]

1. You need to update the pgrx version in Dockerfile.
2. The test_ulid_equals_ulid_operator_unique you added doesn't really fail without your fix (tested in Test for #45 #75), so I am unable to say if your PR fixes it or not. Please first make a commit with just that test and prove that it fails.

[eXsio]

1. Updated Dockerfile
2. Reverted the fix for ERROR: operator is not unique: utils.ulid = utils.ulid in PG 16 #45 - it is not replicable under pgrx conditions and likely is env-dependent. The utils schema from the original ticket had to have some additional config that caused the operator clash. In theory, changing the CAST from IMPLICIT to ASSIGNMENT should alleviate this, but I have no way of proving it via tests. All I really care is adding MAX and MIN, because they fail in currently released version if not used with an explicit cast to either bytea or text.

[pksunkara]

1. Update all rust min versions from 1.85.0 to 1.90.0
2. Use the proper types from pgrx for defining aggregates instead of writing custom sql. https://github.com/pgcentralfoundation/pgrx/blob/develop/articles/postgresql-aggregates-with-rust.md
3. Make sure all tests pass (including formatting and clippy)

[eXsio]

Can you elaborate on point 2?

[pksunkara]

So, what you wrote while is correct, does not use the Aggregrate trait from pgrx. And since we are using pgrx, it's better to leverage that completely instead of using extension_sql!.

Take a look at the article I linked above and you can understand better

[eXsio]

OK, made the changes you requested. Switched to pgrx’s Aggregate trait, made sure cargo format-check passes locally.

[pksunkara]

In theory, changing the CAST from IMPLICIT to ASSIGNMENT should alleviate this, but I have no way of proving it via tests.

I would really appreciate if you have any additional context or idea on how we can test that.