update GH unit test workflow DB

[ericbuckley]

Description

The latest version of pyway, 0.3.30, is not able to read the existing migrations directory. Since these migrations are deprecated in favor of alembic, the easiest path forward is to pin pyway to version 0.3.29 until its removed from the project.

Within #19 we simplified the settings to use the new DB_URI env variable to define connection settings. We forgot to also update update postgres database setup in the GH testing workflow to follow this pattern.

Checklist

Please review and complete the following checklist before submitting your pull request:

• I have ensured that the pull request is of a manageable size, allowing it to be reviewed within a single session.
• I have reviewed my changes to ensure they are clear, concise, and well-documented.
• I have updated the documentation, if applicable.
• I have added or updated test cases to cover my changes, if applicable.
• I have minimized the number of reviewers to include only those essential for the review.
• I have notified teammates in the review thread to build awareness.

Checklist for Reviewers

Please review and complete the following checklist during the review process:

• The code follows best practices and conventions.
• The changes implement the desired functionality or fix the reported issue.
• The tests cover the new changes and pass successfully.
• Any potential edge cases or error scenarios have been considered.