Add .NET 10.0 support to project files and CI workflow

[Copilot]

Overview

This PR adds .NET 10.0 target framework support to all project files in the repository and updates the GitHub Actions CI workflow to build and test against .NET 10.0 when the SDK becomes available.

Changes

Project Files

• PdfJsSharp.csproj: Updated TargetFrameworks from net8.0 to net8.0;net10.0
• PdfJsSharpTests.csproj: Updated TargetFrameworks from net8.0 to net8.0;net10.0

CI/CD Workflow

• .github/workflows/dotnet.yml: Updated all three jobs (build, deployRelease, deployTest) to install both .NET 8.0.x and 10.0.x SDKs using multi-line configuration:

  dotnet-version: |
    8.0.x
    10.0.x

Benefits

• Forward Compatibility: Projects are now configured to target .NET 10.0, enabling seamless transition when the SDK is officially released
• Continuous Testing: CI pipeline will automatically build and test against .NET 10.0 once available, ensuring compatibility
• Multi-Targeting: Maintains backward compatibility with .NET 8.0 while preparing for .NET 10.0

Note

.NET 10.0 is not yet released, so builds will currently only succeed for the .NET 8.0 target. Once Microsoft releases .NET 10.0, the CI workflow will automatically begin building and testing for both frameworks without requiring any additional changes.

Original prompt

Update all project files in the repository to add net10.0 to the TargetFrameworks or TargetFramework property, if not already present. Also, update any GitHub Actions workflow files (e.g., .github/workflows/build.yml) to include .NET SDK version 10.0.x in the build matrix or setup-dotnet steps, ensuring CI builds and tests for .NET 10 as well. Make these updates for all mainline projects and the primary CI build workflow.

This pull request was created as a result of the following prompt from Copilot chat.

Update all project files in the repository to add net10.0 to the TargetFrameworks or TargetFramework property, if not already present. Also, update any GitHub Actions workflow files (e.g., .github/workflows/build.yml) to include .NET SDK version 10.0.x in the build matrix or setup-dotnet steps, ensuring CI builds and tests for .NET 10 as well. Make these updates for all mainline projects and the primary CI build workflow.

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[github-actions]

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