Migrate dependency from serde_yaml to serde_yml

[grittypuffy]

serde-yaml isn't maintained as it can be seen from the Github repo, i. e., that it's archived as of March.

serde-yml is a fork of serde-yaml that's taken an independent route with different goals.

Usage of serde-yml may be beneficial since serde-yaml isn't maintained. However, I would like to hear your opinions on this PR.

I have built the library on my system and there are no breaking changes.

[deg4uss3r]

Hello! I am extremely sorry for the delay here, I usually try to be a bit faster on PRs but this one slipped my mind.

Thank you very much for your contribution but since the suggested crate is still just a sole maintainer and the yaml spec should not be changing anytime soon I would rather keep the original serde_yaml. However, I am going to set up a cargo audit job and watch dependencies more closely for security vulnerabilities and if they become unmaintained.

Thank you again for flagging this!