Update spin to 0.9.3

Author: codecheck01

Cargo.toml

@@ -15,7 +15,7 @@ categories = [ "no-std", "rust-patterns", "memory-management" ]
 exclude = ["/.travis.yml", "/appveyor.yml"]
 
 [dependencies.spin]
-version = "0.9.2"
+version = "0.9.3"
 default-features = false
 features = ["once"]
 optional = true