update Introducing mkosi blog post

[adrelanos]

https://0pointer.net/blog/mkosi-a-tool-for-generating-os-images.html

When you tell mkosi to generate a bootable image for you, it will make it bootable on EFI, not on legacy BIOS.

This is outdated. mkosi is now capable for legacy BIOS booting. This is the reason why I didn't consider using mkosi earlier.

Thank you for adding legacy BIOS booting support!

Also seems like you stopped using the legacy-free branding in this repository, which is fine, but also best if the blog post removes these mentions.

If it's editable in git, happy to send a PR, suggestion.