Add CrackTunes to README.md #1225

Job	Run time
Clippy	46s
Build docs	1m 29s
Test (MSRV)	1m 31s
Rustfmt	5s
Test (stable)	2m 7s
Test (beta)	2m 7s
Test (nightly)	1m 40s
Test (macOS)	1m 34s
Test (Windows)	3m 40s
Test (no features)	1m 24s
Test (all features - simdjson, cargo test --all-features --lib --tests --examples)	1m 13s
Test (native TLS, cargo test --all-features --features serenity/native_tls_backend --lib --tests ...	1m 14s
	18m 50s

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