Upgrade to wasmtime 21.0.1 #6120

Job	Run time
Build Spin Ubuntu	21m 45s
Review new dependencies for known vulnerabilities	30s
Build Spin static (aarch64, aarch64-unknown-linux-musl)	15m 6s
Build Spin (windows-latest)	24m 22s
Run release build steps (ubuntu-20.04, amd64, --features openssl/vendored, target/release)	16m 9s
Build Spin static (amd64, x86_64-unknown-linux-musl)	7m 9s
Build Spin (macos-13)	15m 37s
Run release build steps (ubuntu-20.04, aarch64, --features openssl/vendored --target aarch64-unkn...	17m 6s
Build Spin (macos-14)	9m 24s
Run release build steps (macos-13, amd64, target/release)	22m 48s
all-integration-tests	25m 9s
Lint Rust	9m 3s
Run release build steps (macos-14, aarch64, target/release)	15m 12s
Test Spin (ubuntu-22.04-4core-spin)	8m 1s
Run release build steps (windows-latest, amd64, .exe, target/release)	28m 7s
Test Spin (macos-14)	20m 17s
	4h 15m 45s

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