updated simple lighting shininess.

ScriptableRenderPipeline/LightweightPipeline/LWRP/Materials/Lightweight-StandardSimpleLighting.mat

     - _Mode: 0
     - _Parallax: 0.02
     - _ReflectionSource: 0
-    - _Shininess: 0.15
+    - _Shininess: 0.5
     - _SmoothnessTextureChannel: 0
     - _SpecSource: 0
     - _SpecularHighlights: 1