chore: Use edition 2021 panics #1665

Job	Run time
Check Style	11s
Docs	1m 28s
unstable features	23s
linux / nightly	1m 17s
Android	24s
MSRV	4m 25s
WASM	28s
linux / stable	1s
linux / beta	1s
macOS / stable	2s
windows / stable-x86_64-msvc	1s
windows / stable-i686-msvc	1s
windows / stable-x86_64-gnu	1s
windows / stable-i686-gnu	1s
feat.: default-tls disabled	26s
feat.: rustls-tls	35s
feat.: rustls-tls-manual-roots	40s
feat.: native-tls	25s
feat.: default-tls and rustls-tls	42s
feat.: cookies	35s
feat.: blocking	41s
feat.: gzip	30s
feat.: brotli	41s
feat.: deflate	38s
feat.: json	28s
feat.: multipart	25s
feat.: stream	1s
feat.: socks/default-tls	31s
feat.: socks/rustls-tls	28s
feat.: trust-dns	1s
CI is green	0s
	16m 31s

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