Update Rust crate cargo_metadata to 0.21.0 (#8690)

Author: oxide-renovate[bot]

Cargo.lock

@@ -378,7 +378,7 @@ camino = { version = "1.1", features = ["serde1"] }
 camino-tempfile = "1.4.1"
 camino-tempfile-ext = { version = "0.3.2", features = ["assert-color"] }
 cancel-safe-futures = "0.1.5"
-cargo_metadata = "0.20.0"
+cargo_metadata = "0.21.0"
 chacha20poly1305 = "0.10.1"
 cfg-if = "1.0"
 chrono = { version = "0.4", features = [ "serde" ] }