Bump System.Device.Gpio in /samples/force-sensitive-resistor (#1820)

Bumps [System.Device.Gpio](https://github.com/dotnet/iot) from 2.0.0 to 2.1.0.
- [Release notes](https://github.com/dotnet/iot/releases)
- [Commits](https://github.com/dotnet/iot/compare/2.0...2.1)

---
updated-dependencies:
- dependency-name: System.Device.Gpio
  dependency-type: direct:production
  update-type: version-update:semver-minor
...
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samples/force-sensitive-resistor/force-sensitive-resistor.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Device.Gpio" Version="2.0.0" />
+    <PackageReference Include="System.Device.Gpio" Version="2.1.0" />
     <PackageReference Include="Iot.Device.Bindings" Version="2.1.0" />
   </ItemGroup>