Update dashmap requirement from 5 to 6 (#322) #579

Job	Run time
format	12s
Clippy	49s
cargo-test (ubuntu-22.04, default, stable)	3m 46s
cargo-build (aarch64-linux-android, ubuntu-22.04)	3m 3s
cargo-test (macos-12, default, stable)	12m 16s
cargo-build (armv7-linux-androideabi, ubuntu-22.04)	3m 5s
cargo-test (windows-2019, default, stable)	7m 29s
cargo-build (i686-linux-android, ubuntu-22.04)	2m 59s
cargo-test (ubuntu-22.04, beta)	4m 37s
cargo-build (x86_64-linux-android, ubuntu-22.04)	2m 57s
cargo-test (ubuntu-22.04, blocking)	4m 32s
cargo-build (x86_64-unknown-linux-musl, ubuntu-22.04)	2m 34s
cargo-test (ubuntu-22.04, blocking,beta)	4m 41s
cargo-build (aarch64-apple-ios, macos-12)	4m 26s
cargo-test (ubuntu-22.04, tls-rustls --no-default-features)	4m 49s
cargo-test (ubuntu-22.04, tls-vendored-openssl --no-default-features)	5m 10s
cargo-test (ubuntu-22.04, beta, default)	3m 53s
cargo-test (ubuntu-22.04, 1.74.0, default)	4m 17s
	1h 15m 35s

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