v1 Bug: Errors and erroneous deprecation warning for sync API

[spyoungtech]

Due to a packaging error, files in the sync API were not correctly rewritten from the async API, causing a few errors and erroneous deprecation warnings.

Affects v1.0 and newer

[spyoungtech]

Basically, this problem was caused by python -m build overwriting our _sync directory with vanilla unasync.

This will be addressed in #196

Another option would be to go back to using setup.py sdist bdist_wheel instead, but that wouldn't be ideal.

[spyoungtech]

Resolved in #196 released in 1.1.0