Bump Iot.Device.Bindings in /samples/serialport-arduino (#1389)

Bumps [Iot.Device.Bindings](https://github.com/dotnet/iot) from 1.2.0 to 1.3.0.
- [Release notes](https://github.com/dotnet/iot/releases)
- [Commits](https://github.com/dotnet/iot/compare/1.2...1.3)
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samples/serialport-arduino/serialport-arduino.csproj

@@ -8,7 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="System.Device.Gpio" Version="1.3.0" />
-    <PackageReference Include="Iot.Device.Bindings" Version="1.2.0" />
+    <PackageReference Include="Iot.Device.Bindings" Version="1.3.0" />
   </ItemGroup>
 
 </Project>