There are a couple of things that changed in msgpack 1.0.0 that were
1) The encoding parameter to Unpacker was removed. This has been
deprecated for a while in favor of the `raw` parameter, so this
change switches to using raw.
2) The strict_map_key parameter default was changed from False to
True. I haven't found an explanation of why this was done, but
we can explicitly set it False to maintain the previous behavior.
(cherry picked from commit f19765c683ce847f8d0ae0499d9e67c41114c0b7)