This PR

• Closes Extend submission.create to support attachments #102
• Following on from Add submission attachment API #104 (built on the branch, anticipating the merge)
• Allow passing a list of file paths in the SubmissionService.create() method.
• The files are uploaded as attachments after the submission is created.

If easier, #103 and #104 could be closed and this reviewed & merged all in one go.

What has been done to verify that this works as intended?

I added a test to upload 3 attachment files to one submission:

Why is this the best possible solution? Were any other approaches considered?

• It solves a requirement provided from an existing issue.
• The other approach would be to expect the user to create the submission, then upload attachments separately.
• I think this is a nice addition though, making life significantly easier to creating a submission+attachment combo.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

• This shouldn't really impact the existing API.
• It's additive only changes to the submission create.

Does this change require updates to documentation? If so, please file an issue here and include the link below.

• Updates to the pyodk docs!
• Will look into that if this PR is approved.

Before submitting this PR, please make sure you have:

• included test cases for core behavior and edge cases in tests
• run python -m unittest and verified all tests pass
• run ruff format pyodk tests and ruff check pyodk tests to lint code
• verified that any code or assets from external sources are properly credited in comments