Revise lib/README doc #2357

Job	Run time
build_versions (stable)	2m 48s
build_versions (beta)	2m 43s
Test	30s
build_versions (1.67.0)	3m 19s
Test	1m 2s
Test (charset)	30s
cargo-deny (aarch64-apple-ios)	19s
Test (charset)	38s
cargo-deny (aarch64-linux-android)	21s
Test (cookies)	39s
Test (cookies)	43s
Docs	22s
Test (socks-proxy)	36s
Test (gzip)	33s
Test (socks-proxy)	42s
cargo-deny (i686-pc-windows-gnu)	20s
Test (brotli)	43s
Lint	17s
cargo-deny (i686-pc-windows-msvc)	19s
Test (gzip)	37s
Test (json)	37s
cargo-deny (i686-unknown-linux-gnu)	19s
Test (native-tls)	43s
Test (brotli)	43s
Test (json)	38s
cargo-deny (wasm32-unknown-unknown)	20s
Test (native-tls)	45s
cargo-deny (x86_64-apple-darwin)	24s
cargo-deny (x86_64-apple-ios)	19s
cargo-deny (x86_64-pc-windows-gnu)	19s
cargo-deny (x86_64-pc-windows-msvc)	34s
cargo-deny (x86_64-unknown-linux-gnu)	19s
cargo-deny (x86_64-unknown-redox)	38s
	24m 39s

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