Add version requirement to pyopenjtalk

Hi, it's been running great, but I have to add `>=0.3.0` to the `pyopenjtalk` entry in `requirements.txt`to be able to install it in Windows 10.
Of note, I also need to have MSVC v143 - VS 2022 C++ build tools, C++ CMake for Windows, and Windows 10 SDK from the Visual Studio Community 2022 installer.
I hope this might help others who might have the same problem as me
Thanks!

requirements.txt

@@ -9,7 +9,7 @@ torch
 torchvision
 torchaudio
 unidecode
-pyopenjtalk
+pyopenjtalk>=0.3.0
 jamo
 pypinyin
 ko_pron