Use SHA2 to checksum final release artifacts
Use SHA2 to checksum final release artifacts

[#149148655]

Signed-off-by: Roberto Jimenez Sanchez <138c5d7397106134c5fae60d08c81cdb8dd2d146@gmail.com>

cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release