Migrate CI/CD from AppVeyor to GitHub Actions

[Copilot]

Replaces AppVeyor build pipeline with GitHub Actions workflow.

Changes

• Created .github/workflows/build.yml: Replicates AppVeyor build process (restore, build Release, pack NuGet, upload artifact)
• Updated README.md: Replaced AppVeyor badge with GitHub Actions badge
• Removed appveyor.yml: Deleted legacy configuration and solution file reference
• Migrated to Linux: Changed runner from windows-latest to ubuntu-latest (no Windows dependencies found)

Workflow Configuration

• Runs on ubuntu-latest with .NET SDK from global.json (8.0.416)
• Triggers on push/PR to master
• Minimal permissions (contents: read)
• Uploads CoreFtp.*.nupkg as workflow artifact

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-dotnet@v4
      - run: dotnet restore
      - run: dotnet build CoreFtp.sln --configuration Release --no-restore
      - run: dotnet pack src/CoreFtp/CoreFtp.csproj --no-build --configuration Release
      - uses: actions/upload-artifact@v4

Verification

• ✅ Project has no Windows-specific dependencies
• ✅ Both netstandard1.6 and net452 targets build successfully on Linux
• ✅ Build and pack complete successfully on ubuntu-latest

Original prompt

Migrate from AppVeyor to running in Github build actions.

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[Copilot]

Pull request overview

This PR successfully migrates the CI/CD pipeline from AppVeyor to GitHub Actions, modernizing the build infrastructure while maintaining the same build process. The migration also fixes a path casing issue that existed in the legacy AppVeyor configuration.

Key changes:

• Replaced AppVeyor with GitHub Actions workflow using modern action versions (v4)
• Corrected project path from incorrect CoreFTP to actual CoreFtp casing
• Updated README badge to point to new GitHub Actions build status

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/build.yml	New GitHub Actions workflow replicating AppVeyor build steps (restore, build, pack, upload artifact) with .NET 8.0
appveyor.yml	Removed legacy AppVeyor configuration file
README.md	Updated build status badge from AppVeyor to GitHub Actions
CoreFtp.sln	Removed reference to deleted appveyor.yml file from solution items

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[sparkeh9]

@copilot There's no reason to run the builds here on windows any more. We can just build this on Linux now - check there are no hard windows dependencies, then migrate the codebase to use a default Linux distro

[Copilot]

@copilot There's no reason to run the builds here on windows any more. We can just build this on Linux now - check there are no hard windows dependencies, then migrate the codebase to use a default Li...

Done! Verified that the project has no Windows dependencies and migrated the workflow to use ubuntu-latest. The build completes successfully on Linux, including both the netstandard1.6 and net452 targets. Changes committed in bb2ce1d.