Bump SixLabors.ImageSharp from 3.1.2 to 3.1.3 in /GlennLib (#23)

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](https://github.com/SixLabors/ImageSharp/compare/v3.1.2...v3.1.3)

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

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GlennLib/GlennLib.csproj

@@ -9,7 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="SixLabors.ImageSharp" Version="3.1.2" />
+      <PackageReference Include="SixLabors.ImageSharp" Version="3.1.3" />
     </ItemGroup>
 
     <ItemGroup>