Unify tokio (and serde_json) under workspace dependencies #6725

Job	Run time
Build Spin static (aarch64, aarch64-unknown-linux-musl)	16m 17s
Build Spin (windows-latest)	26m 0s
Build Spin Ubuntu	22m 33s
Build Spin static (amd64, x86_64-unknown-linux-musl)	16m 30s
all-integration-tests	22m 5s
Build Spin (macos-13)	25m 0s
Build Spin (macos-14)	9m 0s
Review new dependencies for known vulnerabilities	23s
Lint Rust	3m 44s
Run release build steps (ubuntu-20.04, amd64, --features openssl/vendored, target/release)	15m 17s
Run release build steps (ubuntu-20.04, aarch64, --features openssl/vendored --target aarch64-unkn...	15m 59s
Test Spin (ubuntu-22.04-4core-spin)	10m 25s
Run release build steps (macos-13, amd64, target/release)	20m 29s
Test Spin (macos-14)	18m 20s
Run release build steps (macos-14, aarch64, target/release)	12m 53s
Run release build steps (windows-latest, amd64, .exe, target/release)	27m 3s
	4h 21m 58s

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