fix: adding support for handling requestBody if its in a $ref

[erunion]

🧰 What's being changed?

This updates @readme/oas-tooling to resolve a bug where operation.getContentType() couldn't handle requestBody schemas that were stored in a $ref. This was exposed as a bug in a multipart/form-data request that was being improperly treated as application/json as since getContentType() didn't see any request bodies, it would default to JSON.

See readmeio/oas#227 for that fix.

Resolves https://app.asana.com/0/1177947654981875/1175486497688586/f

🧪 Testing

You can see this broken here: http://bin.readme.com/s/5f12033dc8a6fe0024c39488

And fixed:

📖 Release Notes

3.5.4 (2020-07-17)

• fix: add support for $ref when pulling content types (Adding support for 426 and 451 HTTP codes. #227) (582968d), closes #227
• build(deps): bump lodash from 4.17.15 to 4.17.19 (Adding support for parameters that may have child $ref pointers. #225) (c4dd657), closes #225
• build(deps): bump lodash from 4.17.15 to 4.17.19 in /packages/tooling (Redesigning the error and loading states in the reference demo #226) (4b6b669), closes #226

3.5.3 (2020-07-16)

• fix: findOperation issues with "/" paths (Update markdown hrefs for ReadMe blog > changelog #223) (ca1cad2), closes #223 /github.com/readmeio/oas/pull/223#discussion_r455448217