build(deps): update wayland-backend requirement from 0.1.0 to 0.2.0

Updates the requirements on [wayland-backend](https://github.com/smithay/wayland-rs) to permit the latest version.
- [Release notes](https://github.com/smithay/wayland-rs/releases)
- [Changelog](https://github.com/Smithay/wayland-rs/blob/master/historical_changelog.md)
- [Commits](https://github.com/smithay/wayland-rs/commits)

---
updated-dependencies:
- dependency-name: wayland-backend
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

gdk4-wayland/Cargo.toml

@@ -32,7 +32,7 @@ gio = {git = "https://github.com/gtk-rs/gtk-rs-core", version = "0.19", features
 glib = {git = "https://github.com/gtk-rs/gtk-rs-core", version = "0.19", features = ["v2_66"]}
 libc = "0.2"
 wayland-client = {version = "0.30.0", optional = true}
-wayland-backend = {version = "0.1.0", optional = true, features = ["client_system"]}
+wayland-backend = {version = "0.2.0", optional = true, features = ["client_system"]}
 khronos-egl = {version = "5.0", optional = true}
 xkb = {version = "0.3", optional = true}