Bump SixLabors.ImageSharp from 3.1.4 to 3.1.5 in /src

Bumps [SixLabors.ImageSharp](https://github.com/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
  update-type: version-update:semver-patch
...

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

src/Directory.Packages.props

@@ -11,7 +11,7 @@
     <PackageVersion Include="NUnit3TestAdapter" Version="4.5.0" />
     <PackageVersion Include="Polyfill" Version="6.0.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.131" />
-    <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.4" />
+    <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.5" />
     <PackageVersion Include="Verify" Version="26.0.0" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.0" />
     <PackageVersion Include="Verify.NUnit" Version="26.0.0" />