Add PinValuePair to list of excluded classes

- No need for it in native code.

***NO_CI***

Author: josesimoes

System.Device.Gpio/System.Device.Gpio.nfproj

@@ -60,6 +60,9 @@
     <NFMDP_PE_ExcludeClassByName Include="ThisAssembly">
       <InProject>false</InProject>
     </NFMDP_PE_ExcludeClassByName>
+    <NFMDP_PE_ExcludeClassByName Include="PinValuePair">
+      <InProject>false</InProject>
+    </NFMDP_PE_ExcludeClassByName>
   </ItemGroup>
   <Import Project="$(NanoFrameworkProjectSystemPath)NFProjectSystem.props" Condition="Exists('$(NanoFrameworkProjectSystemPath)NFProjectSystem.props')" />
   <ItemGroup>