message: [Python] Add MSVC `/utf-8` flag
  The `/utf-8` flag for MSVC is set in [CMakeLists.txt](https://github.com/duckdb/duckdb/blob/d3db91ffbf9b8555d0d9b42087a6f05be04a41b9/CMakeLists.txt#L365), so we should add them to `setup.py`, too.
diff: @@ -102,7 +102,7 @@ os.chdir(os.path.dirname(os.path.realpath(__file__)))
  if os.name == 'nt':
  # windows:
  - toolchain_args = ['/wd4244', '/wd4267', '/wd4200', '/wd26451', '/wd26495', '/D_CRT_SECURE_NO_WARNINGS']
  + toolchain_args = ['/wd4244', '/wd4267', '/wd4200', '/wd26451', '/wd26495', '/D_CRT_SECURE_NO_WARNINGS', '/utf-8']
  else:
  # macos/linux
  toolchain_args = ['-std=c++11', '-g0']
  