Add a shortcut method to get grpc reply

[liuchong]

Motivation:

In many usage cases we will call end and last, give a default shortcut method for this should be convenient I think 👀

Please review when you have time @vietj @tsegismont , thanks!

[vietj]

I like the idea but I think it is too narrow and specific, I created a PR following your idea https://github.com/eclipse-vertx/vertx-grpc/pull/38, please have a look

[liuchong]

I've reviewed your PR and it looks nice! Also maybe this last is still somewhat useful in some certain use cases, as a shortcut, how do you think? 🤔

[vietj]

I think that's too narrow to be here

[liuchong]

ok