[breaking change] Implement HTTP/1/2-only support

[daxpedda]

This PR changes dependencies to be more careful about the default features enabled.
Now HTTP/1 and HTTP/2 are enabled by default but can be disabled if so desired.
There is also now a way to set the server to only enable one of the two protocols.

This would re-open #80 and I have no clue how to solve that without a major redesign of the public API.
The only easier way that comes to mind is cloning the ServerConfig and then modifying the ALPN if it doesn't match while handling the Acceptor.

I will leave this open until the next version upgrade.

[programatik29]

I have no clue how to solve that without a major redesign of the public API.

Me either.

[finnbear]

I'd like to see this API remain available, as I use it to configure many settings for both HTTP/1 and HTTP/2 👀

[daxpedda]

The idea here is to expose anything Builder exposes through axum-servers interface.
What method exactly are you unable to access with the new API?

[finnbear]

Hmm, I don't see how I would access these:

serve
    .http_builder()
    .http1()
    .timer(hyper_util::rt::TokioTimer::new())
    .keep_alive(true)
    .header_read_timeout(Duration::from_secs(5))
    .max_buf_size(32768)
    .http2()
    .timer(hyper_util::rt::TokioTimer::new())
    .keep_alive_interval(Duration::from_secs(16))
    .keep_alive_timeout(Duration::from_secs(5))
    .max_header_list_size(512 * 1024)
    .max_send_buf_size(64 * 1024)
    .max_concurrent_streams(16);

[daxpedda]

Ah yes, I assume if we expose Builder::http1() and Builder::http2() this would cover all the methods you have listed?
The PR should probably be in draft mode.

[giladwolff]

I have an intermediate solution that does not breaks compatibility that can be used, see #156. Let me know what you think.

[finnbear]

Glad it doesn't break compatibility. Still don't personally understand the API or the use-case but you have to convince the maintainer, not me ;)