chore: prep 0.21.0

Author: woodruffw

Cargo.toml

@@ -2,7 +2,7 @@
 name = "github-actions-models"
 authors = ["William Woodruff <[email protected]>"]
 description = "Unofficial, high-quality data models for GitHub Actions workflows, actions, and related components"
-version = "0.20.0"
+version = "0.21.0"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/woodruffw/github-actions-models"