Docs: broken link to policy scoring url

[drewmullen]

on line: https://github.com/mondoohq/packer-plugin-cnspec/blob/main/README.md?plain=1#L59

the link to the policy scoring docs is broken (aka https://mondoo.com/docs/platform/policies/scoring/index.html)

nbd just reporting for awareness

[misterpantz]

#99