[add] empty backend to dependencies.

Author: vmarcella

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "lambda-rs-platform"
-version = "2023.1.26"
+version = "2023.1.27"
 edition = "2021"
 resolver = "2"
 license = "MIT"
@@ -16,6 +16,7 @@ shaderc = "=0.7"
 cfg-if = "=1.0.0"
 rand = "=0.8.5"
 obj-rs = "=0.7.0"
+gfx-backend-empty = "=0.9.0"
 
 # GFX-RS backends
 gfx-backend-gl = { version="=0.9.0", optional = true }