chore(deps): update rust crate specta to v2.0.0-rc.21

Author: renovate[bot]

Cargo.toml

@@ -21,7 +21,7 @@ thiserror = "2"
 url = "2"
 schemars = "0.8"
 dunce = "1"
-specta = "=2.0.0-rc.20"
+specta = "=2.0.0-rc.21"
 # TODO: remove when specta releases rc.21
 specta-util = { version = "^0.0.7", default-features = false, features = [
   "export",