Previously, front matter REQUIRED a layout property (e.g. layout: ../../layouts/MarkdownPostLayout.astro) Now, it's ALSO OK to include your layout as an import in "setup":
setup: |
import Layout from '../../layouts/BlogPost.astro'
import SomeOtherComponent from '../../components/SomeOtherComponent.astro'
4. In .md files, descriptions in square brackets can no longer include double quotation marks. (Single are fine)
X Breaking:

✓ Working:
