chore(deps): bump SixLabors.ImageSharp from 2.1.8 to 2.1.9 in /ShareBook/ShareBook.Helper

[dependabot[bot]]

Bumps SixLabors.ImageSharp from 2.1.8 to 2.1.9.

Release notes

Sourced from SixLabors.ImageSharp's releases.

v2.1.9

What's Changed

• [2.1] Fix overflow in MemoryAllocator.Create(options) by @​antonfirsov in SixLabors/ImageSharp#2732
• Backport GIF LZW fix to 2.1 by @​antonfirsov in SixLabors/ImageSharp#2756
• Backport 2759 to 2.1.x by @​antonfirsov in SixLabors/ImageSharp#2770

Full Changelog: https://github.com/SixLabors/ImageSharp/compare/v2.1.8...v2.1.9

Commits

• 9816ca4 Merge pull request #2770 from SixLabors/af/backport-2759-2.1.x
• b33d666 handle DecodingMode
• 6b2030b Merge branch 'release/2.1.x' into af/backport-2759-2.1.x
• 8ffad3f Issue2012BadMinCode should decode now
• 1f5bf23 skip Issue2758_DecodeWorks
• 3bf8c57 manual port of 3.1 gif decoder
• 28c20de Clamp JPEG quality estimation results.
• 4b910e7 Decode LZW row by row
• a1f2879 Merge pull request #2756 from SixLabors/af/git-av-2.1
• 898df7f backport #2749 to 2.1
• Additional commits viewable in compare view

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