Add chains test to Main (was missing because integration tests are not defined centrally).
Separate problematic pydnatic v1 test in its own env (there were some really strange docker caching issues going on when running it all in the same env before).
Update github action versions to get rid of deprecation warnings.
:rocket: What
:computer: How
:microscope: Testing
https://github.com/basetenlabs/truss/actions/runs/9812634718/job/27097097653