Add publish nuget git action

.github/workflows/publish-nuget.yml

@@ -0,0 +1,34 @@
+name: Build and publish package
+
+# Controls when the action will run. Triggers the workflow on push or pull request
+# events but only for the master branch
+on:
+  push:
+    branches: [ master ]
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  # This workflow contains a single job called "build"
+  build:
+    # The type of runner that the job will run on
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@master
+
+      - name: Setup .NET environment
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '6.0.100'
+
+      - name: Build project
+        working-directory: ./CsvHelper.FastDynamic
+        run: dotnet build --configuration Release
+
+      - name: Generate a NuGet package
+        working-directory: ./CsvHelper.FastDynamic
+        run: dotnet pack --no-build -c Release -o .
+
+      - name: Push to GitHub package registry
+        working-directory: ./CsvHelper.FastDynamic
+        run: dotnet nuget push "*.nupkg" -k ${{secrets.NUGETORGTOKEN}} -s https://api.nuget.org/v3/index.json --skip-duplicate