Vendor dependencies for 0.3.0 release

vendor/bevy_state_macros/src/lib.rs

@@ -0,0 +1,23 @@
+#![expect(missing_docs, reason = "Not all docs are written yet, see #3492.")]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+
+extern crate proc_macro;
+
+mod states;
+
+use bevy_macro_utils::BevyManifest;
+use proc_macro::TokenStream;
+
+#[proc_macro_derive(States, attributes(states))]
+pub fn derive_states(input: TokenStream) -> TokenStream {
+    states::derive_states(input)
+}
+
+#[proc_macro_derive(SubStates, attributes(states, source))]
+pub fn derive_substates(input: TokenStream) -> TokenStream {
+    states::derive_substates(input)
+}
+
+pub(crate) fn bevy_state_path() -> syn::Path {
+    BevyManifest::shared().get_path("bevy_state")
+}