Skip head of existing changelog page

[Cito]

Nice plugin!

Here is an idea that should be simple to implement: When the changelog page already exists, keep everything in it until the first line starting with "- " (markdown for unordered list). Only overwrite the rest. That way, frontmatter with metadata and a head section could be kept in the page.

[badrbouslikhin]

Thanks for your feedback. This should not be complicated to implement, I'll ship it with the next release.