fix: add pytz dependency

[sdebruyn]

resolves #7075

Description

dbt-core uses pytz directly. The dependency on babel guaranteed pytz to be there until now, but that dependency was recently removed. Since dbt-core uses pytz directly (in tracking), it should explicitly add a dependency on it

Checklist

• I have read the contributing guide and understand what's expected of me
• 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 opened an issue to add/update docs, or docs changes are not required/relevant for this PR
• I have run changie new to create a changelog entry

[jtcohen6]

Thanks for the quick work @sdebruyn! We'll need to backport this for inclusion in patch releases of actively supported versions.

[sdebruyn]

@jtcohen6 already on it :)

[jtcohen6]

Amazing - thank you!

I think my US-based colleagues are still asleep. As soon as someone is online, let's get these reviewed & merged & patched & released :)

[sdebruyn]

if you'd be wondering where I got the version constraint from, this is what Babel has so what dbt-core previously had implicitly

[emmyoop]

Look goods. Thanks for the quick work here!

[jcarpenter12]

Thanks for jumping on this so quickly, we spotted this issue this morning impacting some of our ci pipelines