upgrade bosh binary to use official github release
upgrade bosh binary to use official github release

no more pulling something from some random person's s3 bucket

needed because the old binary is a dev version and did not support gcs as a blobstore provider

Signed-off-by: Bin Ju <1363c009d7711c2ee2e4c2e46696f32a73a74f21@pivotal.io>
Co-authored-by: Bohan Chen <c9a015a7f6482b47c219aa2cbd78ba6c88c0a327@pivotal.io>

vito/concourse-bin,vito/concourse-bin