[Justin Hammond (Justintime50)]

Description

Adds SPOD (signature proof of delivery) support for DOCS-239, documented in EasyPost/easypost-web-docs#145. Every Tracker now returns delivery_evidence, an array of {type, image} objects ([] when there is none). type is signature or delivery, and image is a URL to the image, which isn't guaranteed to remain available. The evidence object has no object field.

• Adds deliveryEvidence (List<DeliveryEvidence>) to Tracker
• Adds a DeliveryEvidence model with type and image, following the Surcharge precedent (feat: adds surcharges property and model to Rate object #328)
• Adds a changelog entry under Next Release

Testing

• mvn test -Dtest=TrackerTest (8 tests, passed)
• checkstyle (passed)

Pull Request Type

Please select the option(s) that are relevant to this PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement (fixing a typo, updating readme, renaming a variable name, etc)