New mpy version with 1.9.3. Should we adopt it?

[tannewt]

Upstream bumped the version of mpy again with 1.9.3. The version bump was required due to a reordering of unary bytecodes.

Do we want to inherit this version and require new libs for everyone? Or should we revert this format change and potentially have to bump later if the opcodes are used in a different way later by upstream?

[tannewt]

After sleeping on this I think its best to merge in the bump. Its ok to teach people to look for bundle that match their major version.

I'll do this in #400