This changes the format of the Artifact checksum from SHA1 to SHA256 to
mitigate chosen-prefix and length extension attacks, and ensures it can
be used to secure content against malicious modifications.
Source consumers (including our own {kustomize,helm}-controllers)
should ensure the SHA256 of a downloaded artifact matches the
advertised checksum before making use of it.
Signed-off-by: Hidde Beydals <hello@hidde.co>
fb688ffe8a