fix: Add explicit cargo features for enumn and pyo3 (#425)

Author: waywardmonkeys

common/Cargo.toml

@@ -21,6 +21,8 @@ schemars = { version = "0.8.7", optional = true }
 serde = { version = "1.0", features = ["derive"], optional = true }
 
 [features]
+enumn = ["dep:enumn"]
+pyo3 = ["dep:pyo3"]
 serde = ["dep:serde", "enumn"]
 schemars = ["dep:schemars", "serde"]