While prettier is still outdated internally we should downgrade linting to warning
While prettier is still outdated internally we should downgrade linting to warning

Summary:
We have been getting some builds failing due to incompatible prettier versions, to avoid this we will downgrade prettier linting from error to warning. Once we have prettier internal version being bumped we will then use a `yarn.lock` to lock the prettier version on draft.js to match the internal and bump again the linting rules to `error`
Closes https://github.com/facebook/draft-js/pull/1495

Differential Revision: D6267016

fbshipit-source-id: 0328bae9e452ba0a93bd2b0fef21517d33cce024

facebook/draft-js