These can be added either as files or file urls. This change allows the
Java SDK to send the file or file_urls with the TemplateSignatureRequests. Per the
API documentation, only one type (file vs. file url) can be specified. This
change does not address enforcing that, as it is not enforced in the SignatureRequest
class that this is modeled on.
The HelloSign REST API has support for TemplateSignatureRequests with additional files appended to the end, as documented here: https://app.hellosign.com/api/reference#send_with_template https://app.hellosign.com/api/reference#send_embedded_signature_request_with_template
These can be added either as files or file urls. This change allows the Java SDK to send the file or file_urls with the TemplateSignatureRequests. Per the API documentation, only one type (file vs. file url) can be specified. This change does not address enforcing that, as it is not enforced in the SignatureRequest class that this is modeled on.
Note that this fixes https://github.com/hellosign/hellosign-java-sdk/issues/81