Add support for Content-Type: application/vnd.spring-boot.actuator.v3+json

[Rickroll-C137]

When you visiting the springboot actuator web monitor page, it will return a json string of the opened ports. The problem is that the response Content-Type header is application/vnd.spring-boot.actuator.v3+json, thus can`t be recognized as json string by jsonview.

[stanio]

As far as I can see the regex (#179) needs to be further adjusted to match - (hyphen) and digits:

const jsonContentType = /^application\/([a-z.]+\+)?json($|;)/;