adding in unique_key as a list for incremental models

[McKnight-42]

resolves # CT-134

Description

adding spark implementation of dbt-core recent addition to accept lists as a unique key for incremental models see #4618

• co-author @jtcohen6

Checklist

• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have updated the CHANGELOG.md and added information about my change to the "dbt-spark next" section.

[jtcohen6]

Removing myself from review — feel free to add me back / ping me directly if you have specific questions while working through this!

[McKnight-42]

I tried adding in the databricks_cluster versions of the tests to match how we do other integeration tests for spark and they failed checks so I removed them and added changelog still getting some failures from circleci for spec tests

[VersusFacit]

I'd be fine with merging as is. I think if you played around with the date fields just a touch more, you could get the other tests working, tbh -- at least that's what I gathered from the circleci docs (the main error was the string to date conversion errors). That way, you could also test against the other endpoint. But I don't think it's that necessary since would the behavior really be that different? Probably not.

[McKnight-42]

Date issues found only failing test is unrelated looking into it currently.

[jtcohen6]

@McKnight-42 I think the only remaining failing test is the one I've got a fix for in #301

[McKnight-42]

@McKnight-42 I think the only remaining failing test is the one I've got a fix for in #301

great catch, will review and re run tests against