Metadata write is not atomic

[laurivosandi]

The write_text function used to write config file is not atomic

https://stackoverflow.com/questions/73883435/is-python-3-path-write-text-from-pathlib-atomic

[semekh]

Thanks for pointing that out. I'm aware that some of the actions are non-atomic and they might cause trouble but since those actions are infrequent, I expect them to barely matter. Also, even if things go wrong, the corruption is not FATAL, and should be fairly easy to fix. Those are the reasons I haven't spent time on fixing it yet. That said, PRs are welcome as long they keep it simple.