ANN: snapcraft 2.28 has been released

[Mark Shuttleworth]

What a great release, thank you! Only one request:

On 30/03/17 20:54, Sergio Schvezov wrote:
> ### sources
>
> Sources, thanks to an external contributor, can now make use of a new entry, `source-checksum` which can be added to sources that can be hashed, the format is the following: `source-checksum: <algorithm>/<digest>`. These are the supported algorithms:
>
> - `md5`
> - `sha1`
> - `sha224`
> - `sha256`

Please cull those from the acceptable digests, they are the Fake News of
cryptographic reassurance ;)

Mark