New comment by skmpz on void-packages repository

https://github.com/void-linux/void-packages/pull/29744#issuecomment-813831264

Comment:
ok so I changed py7zr to latest version.. seems that python3-setuptools_scm is enough for building and pyannotate is not needed.. The thing is that some dependencies of py7zr are missing like https://pypi.org/project/ppmd-cffi/ (still in beta version) which also cause calibre 7z suite tests to fail. 
I'll try to get
```
pyzstd>=0.14.4,<0.15.0
ppmd-cffi>=0.3.1,<0.4.0
bcj-cffi>=0.5.0,<0.6.0
multivolumefile>=0.2.0,<0.3.0 
```
added as well.