ci: add NuGet publish workflow (packs + pushes on v* tag)

Author: IPDataInfo

.github/workflows/publish.yml

@@ -0,0 +1,18 @@
+name: Publish
+on:
+  push:
+    tags: ['v*']
+  workflow_dispatch:
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '8.0.x'
+      - run: dotnet restore
+      - run: dotnet build -c Release --no-restore
+      - run: dotnet pack src/IPDataInfo.Sdk/IPDataInfo.Sdk.csproj -c Release --no-build -o out
+      - name: Push to NuGet
+        run: dotnet nuget push "out/*.nupkg" --api-key "${{ secrets.NUGET_API_KEY }}" --source https://api.nuget.org/v3/index.json --skip-duplicate