Updated graphics flag.

unity-default/action.yaml

@@ -30,6 +30,10 @@ inputs:
     description: "Name of the volume to copy the artifacts to."
     required: true
     default: ${{ env.ARTIFACTS_VOLUME }}
+  useGraphics:
+    description: "Whether or not to use the graphics device when running Unity."
+    required: false
+    default: ${{ env.USE_GRAPHICS || 'false' }}
   artifactsDir:
     description: "Name of the directory to copy the artifacts from."
     required: true