Django-s3sign

==================
* Revised upload methods

==================
* Refactored upload logic out of view code
* Added .avif image format.
* Clean up SignS3View method signatures
* Use timezone-aware datetime object in SignS3View

==================
* Recognize heic and heif MIME types.

==================
* Adjust S3Upload.file_dom_selector to allow for any DOM selector
rather than just an ID.
* Introduced new optional param `file_dom_el` for passing in the file
input element directly. This is convenient when initializing
S3Upload from an event, as you can just pass in the event.target
object.

==================
* Fixed bug where `acl` attribute was not working, preventing the
ability to upload objects with `public-read` access.

==================
* Don't call onProgress event handler if file list is empty.