Bump SixLabors.ImageSharp in /src/Lab/Experiments/CoreRTTest (#1978)

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 2.1.6 to 2.1.7.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v2.1.6...v2.1.7)

---
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>

Author: dependabot[bot]

src/Lab/Experiments/CoreRTTest/CoreRTTest.csproj

@@ -10,7 +10,7 @@
 
     <!-- Some tutorials need ImageSharp -->
     <ItemGroup>
-        <PackageReference Include="SixLabors.ImageSharp" Version="2.1.6" />
+        <PackageReference Include="SixLabors.ImageSharp" Version="2.1.7" />
     </ItemGroup>
 
     <!-- Reference Silk.NET -->