Bump SixLabors.ImageSharp from 3.1.2 to 3.1.3 in /ProjectLighthouse

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 3.1.2 to 3.1.3.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v3.1.2...v3.1.3)

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

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

ProjectLighthouse/ProjectLighthouse.csproj

@@ -15,7 +15,7 @@
           <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
         <PackageReference Include="Pfim" Version="0.11.2" />
-        <PackageReference Include="SixLabors.ImageSharp" Version="3.1.2" />
+        <PackageReference Include="SixLabors.ImageSharp" Version="3.1.3" />
         <PackageReference Include="Discord.Net.Webhook" Version="3.13.0" />
         <PackageReference Include="JetBrains.Annotations" Version="2023.3.0" />
         <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="8.0.2" />