ci: Add pack action.

.github/scripts/pack.ps1

@@ -0,0 +1,39 @@
+#!/usr/local/bin/pwsh
+param (
+    [ValidateScript({ ($_ -eq "") -or !(Test-Path $_ -PathType Leaf) })]
+    [string]$OutputPath = "",
+    [ValidateScript({ $_ -ge 0 })]
+    [int]$PullRequestNumber = 0,
+    [ValidateScript({ ($_ -eq "") -or (Test-Path $_) })]
+    [string]$KeyPath = ""
+)
+
+$namespaces = @{
+    ns = "http://schemas.microsoft.com/developer/msbuild/2003"
+}
+$propsPath = "Directory.Build.props"
+$fileVersionPath = "/ns:Project/ns:PropertyGroup/ns:FileVersion"
+$result = Select-Xml -Path $propsPath -Namespace $namespaces -XPath $fileVersionPath
+if ($null -eq $result) {
+    Write-Host "File version not found"
+    exit 1
+}
+
+$fileVersion = $result.Node.InnerText
+$KeyPath = $KeyPath ? $(Resolve-Path -Path $KeyPath) : ""
+$OutputPath = $OutputPath ? [System.IO.Path]::GetFullPath($OutputPath) : ""
+$keyPathExits = Test-Path -Path $KeyPath
+
+Get-ChildItem -Path $OutputPath -Filter "*.nupkg" | ForEach-Object {
+    Remove-Item -Path $_.FullName
+}
+
+$options = @(
+    $OutputPath ? "-o '$OutputPath'" : ""
+    "-p:FileVersion='$fileVersion'"
+    $PullRequestNumber ? "--version-suffix pr.$PullRequestNumber" : ""
+    $keyPathExits ? "-p:TreatWarningsAsErrors=true" : ""
+    $keyPathExits ? "-p:AssemblyOriginatorKeyFile='$KeyPath'" : ""
+) | Where-Object { $_ }
+
+Invoke-Expression -Command "dotnet pack $($options -join " ")"

.github/workflows/pack.yml

@@ -0,0 +1,49 @@
+name: Pack
+
+on:
+  pull_request: 
+  push:
+    branches:
+      - main
+    tags:
+      - "*"
+
+jobs:
+  pack:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4.1.7
+      - uses: actions/setup-dotnet@v4.0.0
+        with:
+          dotnet-version: 8.0.100
+      - run: echo "${{ secrets.SNK_FILE }}" | base64 --decode > private.snk
+      - if: ${{ github.event_name == 'pull_request' }}
+        run: | 
+          .github/scripts/pack.ps1 `
+            -OutputPath "pack" `
+            -PullRequestNumber ${{ github.event.pull_request.number }} `
+            -KeyPath "$pwd/private.snk"
+        shell: pwsh
+      - if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+        run: | 
+          $commitMessage = "$(git log -1 --pretty=%B)"
+          $pattern = "(?<=Merge pull request #)(\d+)"
+          if (!($commitMessage -match $pattern)) {
+            Write-Error "Commit message does not contain a pull request number."
+          }
+
+          Remove-Item -Force -Recurse pack -ErrorAction SilentlyContinue  
+
+          .github/scripts/pack.ps1 `
+            -OutputPath "pack" `
+            -PullRequestNumber $matches[1] `
+            -KeyPath "$pwd/private.snk"
+
+          Get-ChildItem -Path pack -Filter "*.nupkg" | ForEach-Object {
+            dotnet nuget push `
+              $_ `
+              --skip-duplicate `
+              --api-key ${{ secrets.NUGET_API_KEY }} `
+              --source https://api.nuget.org/v3/index.json
+          }
+        shell: pwsh