koa-body should not blacklist body parsing on DELETE requests

[katanacrimson]

koa-body should not blacklist DELETE method for body parsing.

Per RFC 7231 and the HTTP 1.1 specification, it is permitted to send a body with a DELETE request. In order to enable parsing of request bodies for DELETE methods, we have to wholesale disable strict mode, which means we're parsing it for GET and HEAD too - this is not a good solution.

[katanacrimson]

Working on a PR which enables more granular selection of which methods body parsing should be used.

This will also result in a compatibility shim for strict mode, allowing its continued use, but would effectively deprecate it.

[doums]

I'm agree with you, it's just annoying that we can't use the body's request when using an http DELETE request..