Fixed lightweight unlit shader tag.

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightUnlit.shader

     }
     SubShader
     {
-        Tags { "RenderType" = "Opaque" "IgnoreProjectors" = "True" "RenderPipeline" = "LightweightPipe" }
+        Tags { "RenderType" = "Opaque" "IgnoreProjectors" = "True" "RenderPipeline" = "LightweightPipeline" }
         LOD 100
 
         Blend [_SrcBlend][_DstBlend]
             ENDHLSL
         }
     }
+    FallBack "Hidden/InternalErrorShader"
     CustomEditor "LightweightUnlitGUI"
 }