bump maturin to 1.9.4, drop extension-module feature

Author: davidhewitt

Cargo.toml

@@ -51,10 +51,6 @@ hex = "0.4.3"
 name = "_pydantic_core"
 crate-type = ["cdylib", "rlib"]
 
-[features]
-# must be enabled when building with `cargo build`, maturin enables this automatically
-extension-module = ["pyo3/extension-module"]
-
 [profile.release]
 lto = "fat"
 codegen-units = 1

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ['maturin>=1.9,<2']
+requires = ['maturin>=1.9.4,<2']
 build-backend = 'maturin'
 
 [project]
@@ -97,7 +97,6 @@ all = [
 python-source = "python"
 module-name = "pydantic_core._pydantic_core"
 bindings = 'pyo3'
-features = ["pyo3/extension-module"]
 
 [tool.ruff]
 line-length = 120