Add jobs for package publishing

- Add NuGet push to production job `nuget-push-prod`.
- Add NuGet push to development job `nuget-push-dev`.
- Add job `release-artifacts` to upload `.nuget` to the GitHub Release corresponding to the current tag (if any).

.github/workflows/dotnet.yml

@@ -3,6 +3,7 @@ name: dotnet
 on:
   push:
     branches: [master]
+    tags: ["*"]
   pull_request:
     branches: [master]
 
@@ -18,12 +19,12 @@ jobs:
         with:
           fetch-depth: 0
 
-      - uses: gittools/actions/gitversion/setup@v0.9.3
+      - uses: gittools/actions/gitversion/setup@v0.9.4
         with:
           versionSpec: "5.x"
 
       - id: gitversion
-        uses: gittools/actions/gitversion/execute@v0.9.3
+        uses: gittools/actions/gitversion/execute@v0.9.4
 
       - uses: actions/setup-dotnet@v1
         with:
@@ -55,18 +56,74 @@ jobs:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         run: bash <(curl -s https://codecov.io/bash)
 
-      - name: NuGet Pack
-        run: |
+      - run: |
           dotnet pack \
             --include-source \
             --configuration Release \
             --no-build \
             --no-restore \
             -p:PackageVersion="${{ steps.gitversion.outputs.fullSemVer }}" \
             src/json-ld.net/json-ld.net.csproj \
-            --output nugets/
+            --output ${{ github.workspace }}/nugets/
 
       - uses: actions/upload-artifact@v2
         with:
           name: nugets
           path: nugets
+
+  nuget-push-dev:
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/') != true
+    needs: build
+
+    steps:
+      - uses: actions/download-artifact@v2
+        with:
+          name: nugets
+
+      - uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: 2.1.401
+          source-url: https://nuget.pkg.github.com/linked-data-dotnet/json-ld.net/index.json
+        env:
+          NUGET_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+
+      - run: dotnet nuget push nugets/*.nupkg --source https://nuget.pkg.github.com/linked-data-dotnet/json-ld.net/index.json --skip-duplicate
+
+  nuget-push-prod:
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/')
+    needs: build
+
+    steps:
+      - uses: actions/download-artifact@v2
+        with:
+          name: nugets
+
+      - uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: 2.1.401
+          source-url: https://api.nuget.org/v3/index.json
+        env:
+          NUGET_AUTH_TOKEN: ${{ secrets.NUGET_API_KEY }}
+
+      - run: dotnet nuget push nugets/*.nupkg --skip-duplicate
+
+  release-artifacts:
+    runs-on: ubuntu-latest
+    needs: build
+    if: startsWith(github.ref, 'refs/tags/')
+
+    steps:
+      - uses: actions/download-artifact@v1
+        with:
+          name: nugets
+
+      - name: Upload to stable release
+        uses: svenstaro/upload-release-action@v1-release
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          file: nugets
+          asset_name: json-ld.net
+          tag: ${{ github.ref }}
+          overwrite: true