Add limits for mesh shaders (#149)

Added newer Limit enum variants to support
working with mesh shaders, following the
original C header and Rust API guidelines.

https://github.com/google/shaderc/blob/65fa097f2f0aae1a9c233bcf7d03ca3dcd296c6e/libshaderc/include/shaderc/shaderc.h#L192-L210

shaderc-rs/src/lib.rs

@@ -398,6 +398,25 @@ pub enum Limit {
     MaxCullDistances,
     MaxCombinedClipAndCullDistances,
     MaxSamples,
+    MaxMeshOutputVerticesNv,
+    MaxMeshOutputPrimitivesNv,
+    MaxMeshWorkGroupSizeXNv,
+    MaxMeshWorkGroupSizeYNv,
+    MaxMeshWorkGroupSizeZNv,
+    MaxTaskWorkGroupSizeXNv,
+    MaxTaskWorkGroupSizeYNv,
+    MaxTaskWorkGroupSizeZNv,
+    MaxMeshViewCountNv,
+    MaxMeshOutputVerticesExt,
+    MaxMeshOutputPrimitivesExt,
+    MaxMeshWorkGroupSizeXExt,
+    MaxMeshWorkGroupSizeYExt,
+    MaxMeshWorkGroupSizeZExt,
+    MaxTaskWorkGroupSizeXExt,
+    MaxTaskWorkGroupSizeYExt,
+    MaxTaskWorkGroupSizeZExt,
+    MaxMeshViewCountExt,
+    MaxDualSourceDrawBuffersExt,
 }
 
 /// An opaque object managing all compiler states.