Add Wayland dev package dependency info to `README.md`.

[xStrom]

I just did a fresh Ubuntu 23.04 install and was greeted with the following error when attempting to build with the wayland feature:

error: failed to run custom build command for `wayland-sys v0.30.1`

Caused by:
  process didn't exit successfully: `/home/strom/Rust/glazier/target/debug/build/wayland-sys-23ce904e0e81cf94/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=WAYLAND_CLIENT_NO_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG
  cargo:rerun-if-env-changed=WAYLAND_CLIENT_STATIC
  cargo:rerun-if-env-changed=WAYLAND_CLIENT_DYNAMIC
  cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
  cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR

  --- stderr
  thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: `PKG_CONFIG_ALLOW_SYSTEM_CFLAGS="1" PKG_CONFIG_ALLOW_SYSTEM_LIBS="1" "pkg-config" "--libs" "--cflags" "wayland-client"` did not exit successfully: exit status: 1
  error: could not find system library 'wayland-client' required by the 'wayland-sys' crate

  --- stderr
  Package wayland-client was not found in the pkg-config search path.
  Perhaps you should add the directory containing `wayland-client.pc'
  to the PKG_CONFIG_PATH environment variable
  Package 'wayland-client', required by 'virtual:world', not found
  ', /home/strom/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-sys-0.30.1/build.rs:10:47
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed

Doing apt install libwayland-dev solved the issue and so this PR adds that info to the readme here. I didn't test Fedora, I just looked up the package name.

[DJMcNab]

Thanks! Seems an obvious thing to miss. For reference, this is a consequence of adopting raw-window-handle (and more generally, being able to use Vulkan to render to surfaces). Ideally, the Vulkan spec would support this in a different way, but that seems very unlikely

I haven't checked this on Fedora out due to being on mobile.