The script that generates the header file is not available

When I delete the header file under `capi/include`, run the command: 
```SH
(base) spongehah@MacBook capi % ./gen_header.sh
cp: /Users/spongehah/Document/src/hyper/capi/include/hyper.h: No such file or directory
rm: /Users/spongehah/Document/src/hyper/capi/include/hyper.h.backup: No such file or directory
```
