I can’t render the dashboard in quarto R

ERROR: In file C:UserswwaneDownloadsdiamonds.qmd
(line 3, columns 9--18) Field "format" has value dashboard, which must instead be 'asciidoc'
2: title: "Diamonds Explorer"
3: format: dashboard
          ~~~~~~~~~~
4: server: shiny

ERROR: Render failed due to invalid YAML.

it is showing an error the YAML