Allow `HEAD` request about fastapi-health

[perezzini]

Yes! Haven't noticed, sorry! 😅. Thanks for your reply @Kludex and for your contribution implementing fastapi-health.

[perezzini]

(Think this is important given that some healthcheck utils make HEAD requests, instead of GET requests by default)

[Kludex]

I can see that FastAPI, for the moment, does not automatically support HEAD method for GET routes (see: tiangolo/fastapi#1773).

If you go further on that issue, you'll see that I've implemented two PRs to add HEAD there. 😅

You can just manually add the methods=["GET", "HEAD"], there's nothing that needs to be added on the fastapi-health itself.