[DW-27] Update SixLabour.ImageSharp due to vulnerability report

[first-ironsoftware]

Update SixLabour.ImageSharp due to vulnerability report

Description

Upgrade SixLabour.ImageSharp to the version 2.1.9 for .netstandard 2.0 dependencies from this report: https://github.com/advisories/GHSA-63p8-c4ww-9cg7

Fixes #DW-27

Type of change

Please select the relevant option by placing an 'x' inside the brackets, like this: [x].

• [ ] 🐛 Bug fix (non-breaking change which fixes an issue)
• [ ] ✨ New feature (non-breaking change which adds functionality)
• [ ] 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] 🏗️ Internal/structural update (non-breaking change that improves code quality, organization, or performance)
• [ ] 📚 This change requires a documentation update
• [ ] 🚀 DevOps build chain modification for release
• [ ] 🤖 DevOps build chain modification for CI

How Has This Been Tested?

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Checklist:

Please run through the checklist as much as possible and mark the items completed by placing an 'x' inside the brackets, like this: [x].

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] I have successfully run all unit tests on Windows
• [x] I have successfully run all unit tests on Linux

Additional Context

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