Bump SixLabors.ImageSharp from 1.0.3 to 2.1.7 in /Utils/Image2PAA

Bumps [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp) from 1.0.3 to 2.1.7.
- [Release notes](https://github.com/SixLabors/ImageSharp/releases)
- [Commits](SixLabors/ImageSharp@v1.0.3...v2.1.7)

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

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

Utils/Image2PAA/Image2PAA.csproj

@@ -6,7 +6,7 @@
  </PropertyGroup>
  <ItemGroup>
  <PackageReference Include="CommandLineParser" Version="2.8.0" />
- <PackageReference Include="SixLabors.ImageSharp" Version="1.0.3" />
+ <PackageReference Include="SixLabors.ImageSharp" Version="2.1.7" />
  </ItemGroup>
 
  <ItemGroup>