v1.0.0-rc1

Welcome to another release of the go-digest package. This package
provides a simple toolkit for working with the digests of container
images.

In this release, we've mostly narrowed the acceptable format for
sha256 digests, which are the most common in use. Specifically, upper
case hex-encoded characters are no longer allowed in that format,
removing the ambiguity in encoding.

Other concessions have been made to allow separators in the algorithm,
as well as allowing the character set of the urlsafe base64 encodings.
Most of this is more about allowing support for future formats, and are
not officially supported at this time.

Changes

279bed9 Merge pull request #34 from AkihiroSuda/regexp
4ca1301 disallow upper characters (/A-F/) in hex-encoded portion
eaa6054 Merge pull request #33 from stevvooe/future-proof-algorithm-field
678a95e digest: allow validation of urlsafe base64 encoding
55f6758 digest: update package methods to reflect changes
5ab10f5 digest: allow separators in algorithm field