* lisp/use-package/use-package-core.el (use-package-vc-prefer-newest):
User option to prefer the latest commit (as opposed to the latest
release) of a package.
(use-package-normalize--vc-arg): Check for
use-package-vc-prefer-newest.
* doc/misc/use-package.texi (Install package): Document
use-package-vc-prefer-newest.
* etc/NEWS: Document use-package-vc-prefer-newest.