Bump Iot.Device.Bindings in /samples/serialport-arduino (dotnet#1772)

Bumps [Iot.Device.Bindings](https://github.com/dotnet/iot) from 1.5.0 to 2.0.0.
- [Release notes](https://github.com/dotnet/iot/releases)
- [Commits](dotnet/iot@1.5...2.0)

---
updated-dependencies:
- dependency-name: Iot.Device.Bindings
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

samples/serialport-arduino/serialport-arduino.csproj

@@ -8,7 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="System.Device.Gpio" Version="2.0.0" />
-    <PackageReference Include="Iot.Device.Bindings" Version="1.5.0" />
+    <PackageReference Include="Iot.Device.Bindings" Version="2.0.0" />
   </ItemGroup>
 
 </Project>