Bump SixLabors.ImageSharp from 3.1.5 to 3.1.6

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 3.1.5 to 3.1.6.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v3.1.5...v3.1.6)

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

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

src/BlurHashSharp.ImageSharp/BlurHashSharp.ImageSharp.csproj

@@ -22,7 +22,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.5" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.6" />
   </ItemGroup>
 
   <ItemGroup>