bump bytefmt
bump bytefmt

Submodule src/code.cloudfoundry.org/bytefmt 24c06ce..b12c152:
  > README: update godoc URL

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release