[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 that expires after 30 days. The evidence object has no object field.

• Documents delivery_evidence as DeliveryEvidence[] on Tracker
• Adds a docblock-only DeliveryEvidence class with type and image, and requires it in lib/easypost.php. This mirrors Message, which also has no object field. It isn't added to OBJECT_MAPPING because that mapping keys on object, so the items stay EasyPostObject at runtime
• Adds a changelog entry under Next Release

Testing

• Docblock-only change, so there are no new tests
• composer lint, composer phpstan, composer scan and composer test (203 tests, 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)