Hello!
It will be great to add a support for different reporters, like JUnit. The option to CLI will be someting like --formatter=prettier-formatter-junit where prettier-formatter-junit will be an external reporter plugin.

Environments:

• Prettier Version: 2.4.1
• Running Prettier via: CLI
• Runtime: Nodejs
• Operating System: CI machine

Steps to reproduce:

prettier -l "**/*.{md,css,scss,yaml,yml,ts}"

Expected behavior:
Added --formatter=prettier-formatter-junit option. It also will be great to add the diff first like it mention in #6885

Actual behavior:
No support for reporters