JsonStrategy should NOT set response charset with application/json

[ademarre]

Wrong:
Content-Type: application/json; charset=utf-8

Right:
Content-Type: application/json

JsonStrategy adds the charset parameter to the application/json content type, which is not compliant with the spec.

https://tools.ietf.org/html/rfc7159#section-11:

No "charset" parameter is defined for this registration. Adding one really has no effect on compliant recipients.

The incorrect behavior was introduced here:
zendframework/zendframework#2629
zendframework/zendframework#3483

[weierophinney]

This repository has been closed and moved to laminas/laminas-view; a new issue has been opened at laminas/laminas-view#26.