feat: allow enabling http1/http2 individually #254

Job	Run time
Check Style	8s
Test with Miri	43s
features	46s
Check MSRV (1.63)	1m 13s
Test stable on ubuntu-latest	33s
Test stable on windows-latest	2m 13s
Test stable on macOS-latest	45s
Test beta on ubuntu-latest	28s
Test beta on windows-latest	1m 4s
Test beta on macOS-latest	1m 3s
Test nightly on ubuntu-latest	30s
Test nightly on windows-latest	56s
Test nightly on macOS-latest	1m 5s
Build docs	13s
CI is green	1s
	11m 41s

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