autoroll: Add "release" target to Makefile
autoroll: Add "release" target to Makefile

BUG=skia:

Review-Url: https://codereview.chromium.org/2267903002

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot