message: fix(new): Use new frontmatter format
diff: @@ -166,7 +166,8 @@ const DEFAULT_LAYOUT: &str = "<!DOCTYPE html>
  </html>
  ";
  -const POST_MD: &str = "layout: default.liquid
  +const POST_MD: &str = "---
  +layout: default.liquid
  title: First Post
  is_draft: true
  @@ -177,7 +178,8 @@ is_draft: true
  Welcome to the first post ever on cobalt.rs!
  ";
  -const INDEX_MD: &str = "layout: default.liquid
  +const INDEX_MD: &str = "---
  +layout: default.liquid
  ---
  ## Blog!
  