Fix minimal working serde version

Author: dhardy

Cargo.toml

@@ -28,4 +28,4 @@ all-features = true
 serde = ["dep:serde"] # enables serde for BlockRng wrapper
 
 [dependencies]
-serde = { version = "1", features = ["derive"], optional = true }
+serde = { version = "1.0.103", features = ["derive"], optional = true }