Bump SixLabors.ImageSharp from 3.1.6 to 3.1.7 in /src#640

SimonCropp merged 1 commit intomainVerifyTests/Verify.ImageSharp:mainfrom

dependabot/nuget/src/SixLabors.ImageSharp-3.1.7VerifyTests/Verify.ImageSharp:dependabot/nuget/src/SixLabors.ImageSharp-3.1.7Copy head branch name to clipboard