Release v3.0.1

Added

• Polyfill function (#19).

Changed

• [breaking] Uncompat now returns ([]H3Index, error) instead of []H3Index
  to accommodate error scenario from C API (#19).

Fixed

• panic when using Uncompact with invalid resolutions (#20).
• latitudes and longitudes outside of respective ranges when unprojecting in
  certain areas (#7, #9, #13).