Do not enable json by default #2716

Job	Run time
Lint	38s
Docs	1m 44s
build_versions (stable)	2m 52s
Test	53s
build_versions (beta)	2m 58s
Test	43s
Test (charset)	54s
cargo-deny (aarch64-apple-ios)	18s
build_versions (1.71.1)	2m 41s
Test (charset)	1m 9s
Test (cookies)	1m 4s
cargo-deny (aarch64-linux-android)	24s
Test (cookies)	59s
Test (socks-proxy)	52s
cargo-deny (i686-pc-windows-gnu)	21s
Test (socks-proxy)	43s
Test (gzip)	57s
cargo-deny (i686-pc-windows-msvc)	21s
Test (gzip)	53s
Test (brotli)	54s
cargo-deny (i686-unknown-linux-gnu)	20s
Test (json)	56s
Test (brotli)	43s
cargo-deny (wasm32-unknown-unknown)	20s
Test (json)	1m 15s
Test (native-tls)	59s
cargo-deny (x86_64-apple-darwin)	18s
Test (native-tls)	56s
cargo-deny (x86_64-apple-ios)	20s
Test (rustls-no-provider)	52s
cargo-deny (x86_64-pc-windows-gnu)	17s
cargo-deny (x86_64-pc-windows-msvc)	21s
cargo-deny (x86_64-unknown-linux-gnu)	18s
cargo-deny (x86_64-unknown-redox)	17s
	30m 30s

Provide feedback