Bump SixLabors.ImageSharp

Bumps the nuget group with 1 update in the /s3-lambda-dotnet/ImageResize directory: [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp).


Updates `SixLabors.ImageSharp` from 3.1.4 to 3.1.5
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v3.1.4...v3.1.5)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

s3-lambda-dotnet/ImageResize/ImageResize.csproj

@@ -15,6 +15,6 @@
     <PackageReference Include="Amazon.Lambda.Serialization.SystemTextJson" Version="2.3.1" />
     <PackageReference Include="Amazon.Lambda.S3Events" Version="3.0.0" />
     <PackageReference Include="AWSSDK.S3" Version="3.7.104.2" />
-    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.4" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.5" />
   </ItemGroup>
 </Project>