Adding release action

Author: Matt Hunt

.github/workflows/release.yml

@@ -0,0 +1,55 @@
+name: 'Release' 
+
+on:
+  release:
+    types: 
+      - published
+
+env:
+  DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
+  DOTNET_CLI_TELEMETRY_OPTOUT: true
+  
+  # Project name to pack and publish
+  PROJECT_NAME: GeoJSON.Net
+
+   # Official NuGet Feed settings
+  NUGET_FEED: https://api.nuget.org/v3/index.json
+  NUGET_KEY: ${{ secrets.NUGET_KEY }}
+  NUGET_VERSIONING_REGEX: "[0-9]+\\.[0-9]+\\.[0-9]+(-[a-zA-Z]+)?"  
+
+jobs:
+  deploy:
+    name: 'Deploy to Nuget'
+    if: github.event_name == 'release'
+    runs-on: windows-2019
+
+    steps:
+      - name: Validate release version
+        run: |
+          $VERSION=${env:GITHUB_REF_NAME}
+          if($VERSION[0] -eq "v"){
+            $VERSION=$VERSION.substring(1)
+          }
+          if(!($VERSION -match ${env:NUGET_VERSIONING_REGEX})) {
+            throw "Release tag did not contain a valid NUGET version. TAG was : ${env:GITHUB_REF_NAME}"
+          }
+          echo "Version to use is - $VERSION"
+          echo "RELEASE_VERSION=$VERSION" | Out-File -FilePath ${env:GITHUB_ENV} -Append
+      - uses: actions/checkout@v2 
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: |
+            3.1.x
+            5.0.x
+            6.0.x
+            7.0.x
+            8.0.x
+      - name: Install dependencies
+        run: dotnet restore src/${{ env.PROJECT_NAME }}.sln
+      - name: Build solution
+        run: dotnet build src/${{ env.PROJECT_NAME }}.sln -c Release --no-restore
+      - name: Create Release NuGet package
+        run: dotnet pack -v normal -c Release --include-symbols --include-source -p:PackageVersion=${{ env.RELEASE_VERSION }} -o nupkg src/${{ env.PROJECT_NAME }}/${{ env.PROJECT_NAME }}.csproj
+      - name: Push to Nuget
+        run: dotnet nuget push "./nupkg/${{ env.PROJECT_NAME }}.${{ env.RELEASE_VERSION }}.nupkg" --source https://api.nuget.org/v3/index.json --api-key ${{secrets.NUGET_KEY}} --skip-duplicate