crate: update optional dependency `riscv` to 0.10.0

This dependency is only used when `machine` feature is enabled.

Cargo.toml

@@ -17,7 +17,7 @@ edition = "2021"
 
 [dependencies]
 sbi-spec = "0.0.4"
-riscv = { version = "0.9.0", optional = true }
+riscv = { version = "0.10.0", optional = true }
 
 [features]
 default = ["machine"]