Non-ASCII characters in filename throws error.

[simonliu99]

OSError: Command failed: C:\Program Files\wkhtmltopdf\bin\wkhtmltopdf.exe https://dingdong.com/bong.html C:\Users\chong\Code\β-Lactam Cell Wall Inhibitors.pdf Check whhtmltopdf output without 'quiet' option [Errno 2] No such file or directory: 'C:\Users\chong\Code\β-Lactam Cell Wall Inhibitors.pdf'

Looks like passing β in the filename causes failure.