Bump version to v2.28.0 (#1615)

Also bump pyo3 to 0.23.4.

Author: Viicos

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "pydantic-core"
-version = "2.27.2"
+version = "2.28.0"
 edition = "2021"
 license = "MIT"
 homepage = "https://github.com/pydantic/pydantic-core"
@@ -29,7 +29,7 @@ rust-version = "1.75"
 [dependencies]
 # TODO it would be very nice to remove the "py-clone" feature as it can panic,
 # but needs a bit of work to make sure it's not used in the codebase
-pyo3 = { version = "0.23.3", features = ["generate-import-lib", "num-bigint", "py-clone"] }
+pyo3 = { version = "0.23.4", features = ["generate-import-lib", "num-bigint", "py-clone"] }
 regex = "1.11.1"
 strum = { version = "0.26.3", features = ["derive"] }
 strum_macros = "0.26.4"