Bump SixLabors.ImageSharp from 2.1.6 to 3.1.2

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 2.1.6 to 3.1.2.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v2.1.6...v3.1.2)

---
updated-dependencies:
- dependency-name: SixLabors.ImageSharp
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

samples/Samples.Upload/Samples.Upload.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="SixLabors.ImageSharp" Version="2.1.6" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.2" />
   </ItemGroup>
 
   <ItemGroup>