Bump SixLabors.ImageSharp in /src/Contacts.ImageManager

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 3.0.2 to 3.1.5.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v3.0.2...v3.1.5)

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

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

src/Contacts.ImageManager/Contacts.ImageManager.csproj

@@ -11,7 +11,7 @@
 
     <ItemGroup>
       <PackageReference Include="JosephGuadagno.AzureHelpers.Storage" Version="1.1.6" />
-      <PackageReference Include="SixLabors.ImageSharp" Version="3.0.2" />
+      <PackageReference Include="SixLabors.ImageSharp" Version="3.1.5" />
     </ItemGroup>
 
 </Project>