`fetch()` and client-side websocket used to support HTTP/2, but this
regressed in #11491. This patch reenables it by explicitly adding `h2`
and `http/1.1` to the list of ALPN protocols on the HTTP and websocket
clients.
This adds support for using in memory CA certificates for
`Deno.startTLS`, `Deno.connectTLS` and `Deno.createHttpClient`.
`certFile` is deprecated in `startTls` and `connectTls`, and removed
from `Deno.createHttpClient`.
