replace `requests` with `httpx`

[FHU-yezi]

httpx is a requests-like Python network package. It can be a drop-in replacement of requests.

HTTPX GitHub Repo

Documentation

Just search for any use of requests and I only found the command line tool pc use it, for a subcommand deploy which is unused now, so feel free to leave it there until we release the deploy feature.

[picklelo]

Thanks, we will update this.