Update references of older net versions with new

[specialforest]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, agent, or skill file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, or skill with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.

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Description

Updated references to .NET6 with .NET8 since .NET6 reached end of life.
Updated references to .NET8 with .NET10 as the latest LTS.

Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New collection file.
• New skill file.
• Update to existing instruction, prompt, agent, collection or skill.
• Other (please specify):

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Additional Notes

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[Copilot]

Pull request overview

This pull request updates .NET version references throughout the upgrade documentation, replacing references to .NET 6 (which reached end of life) with .NET 8, and updating examples from .NET 8 to .NET 10. However, there is a fundamental issue with the PR's premise: it incorrectly identifies .NET 10 as an LTS (Long Term Support) release when it is actually an STS (Standard Term Support) release with only 18 months of support. .NET 8 is the current LTS release, supported until November 2026.

Changes:

• Updated target framework examples from net8.0 to net10.0
• Updated migration recommendations from ".NET 6+" to ".NET 8+"
• Updated configuration change references from ".NET 6+" to ".NET 8+"
• Updated intermediate migration steps from ".NET 6+" to ".NET 8+"

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
instructions/dotnet-upgrade.instructions.md	Updated multiple examples and recommendations to reference .NET 10 as the latest LTS (incorrect - it's STS) and .NET 8+ as migration baseline
agents/dotnet-upgrade.agent.md	Updated intermediate migration step reference from .NET 6+ to .NET 8+