Merge pull request #1528 from Unity-Technologies/lw/fix-shadergraph-shadowtypo

Fixed wrong keyword in shader graph shadow template

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/lightweightPBRForwardPass.template

     #pragma multi_compile _ _SHADOWS_ENABLED
     #pragma multi_compile _ _LOCAL_SHADOWS_ENABLED
     #pragma multi_compile _ _SHADOWS_SOFT
-    #pragma multi_compile _ _SHADOWS_CASCADES
-
+    #pragma multi_compile _ _SHADOWS_CASCADE
+    
 	// -------------------------------------
     // Unity defined keywords
     #pragma multi_compile _ DIRLIGHTMAP_COMBINED