cargo: add experimental feature for unreleased protocols

Cargo.toml

@@ -45,6 +45,7 @@ wayland-scanner = "0.29"
 [features]
 default = []
 debug = ["egui", "smithay-egui", "serde_json"]
+experimental = []
 
 [profile.dev]
 lto = "thin"

src/wayland/mod.rs

@@ -2,5 +2,7 @@
 mod drm;
 pub use drm::*;
 
+#[cfg(feature = "experimental")]
 mod workspace;
+#[cfg(feature = "experimental")]
 pub use workspace::*;