Update sysinfo to 0.21

Author: WilliamVenner

Cargo.lock

@@ -14,5 +14,5 @@ codegen-units = 1
 [dependencies]
 libloading = "0.7"
 lazy_static = "1.4"
-sysinfo = { version = "0.20", default-features = false }
+sysinfo = { version = "0.21", default-features = false }
 crossbeam = { version = "0.8", default-features = false, features = ["crossbeam-channel", "std"] }