Bump SixLabors.ImageSharp (dotnet#1973)

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 2.1.6 to 3.1.3.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v2.1.6...v3.1.3)

---
updated-dependencies:
- dependency-name: SixLabors.ImageSharp
  dependency-type: direct:production
...

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

examples/CSharp/OpenGL Tutorials/Tutorial 2.2 - Camera/Tutorial 2.2 - Camera.csproj

@@ -8,7 +8,7 @@
  </PropertyGroup>
 
  <ItemGroup>
- <PackageReference Include="SixLabors.ImageSharp" Version="2.1.6" />
+ <PackageReference Include="SixLabors.ImageSharp" Version="3.1.3" />
  </ItemGroup>
 
  <ItemGroup>