Enable Dependabot updates to Poetry lockfile

[d33bs]

Description

This PR focuses on long-term sustainability for this project by enabling Dependabot to automatically update the Poetry lockfile. Normally this is a task which must be performed manually. By enabling this change we can have Dependabot automatically update the dependency references (which still fall into the constraints of the pyproject.toml file).

Thanks for any feedback!

What is the nature of your change?

• Content additions or updates (adds or updates content)
• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (these changes would cause existing functionality to not work as expected).

Checklist

Please ensure that all boxes are checked before indicating that this pull request is ready for review.

• I have read the CONTRIBUTING.md guidelines.
• My code follows the style guidelines of this project.
• I have performed a self-review of my own contributions.
• I have commented my content, particularly in hard-to-understand areas.
• I have made corresponding changes to related documentation (outside of book content).
• My changes generate no new warnings.
• New and existing tests pass locally with my changes.
• I have added tests that prove my additions are effective or that my feature works.
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[d33bs]

Thank you @gwaybio ! Merging this in.