Add prerelease build

.github/workflows/prerelease.yml

@@ -0,0 +1,30 @@
+name: .NET Core Build
+
+on:
+  push:
+    branches:
+      - prerelease
+  pull_request:
+    branches: [ prerelease ]
+
+jobs:
+  build:
+
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 8.0.x
+    - name: Install NUnit.ConsoleRunner
+      run: nuget install NUnit.ConsoleRunner -Version 3.17.0 -DirectDownload -OutputDirectory .       
+    - name: Install dependencies
+      run: dotnet restore
+    - name: Build
+      run: dotnet build --configuration Release --no-restore /p:version=2.0.${{ github.run_number }}-prerelease
+    - name: Tests
+      run: ./NUnit.ConsoleRunner.3.17.0/tools/nunit3-console.exe  "Sharp7.Rx.Tests\bin\Release\net461\Sharp7.Rx.Tests.dll"
+    - name: NugetPublish
+      run: dotnet nuget push Sharp7.Rx\bin\Release\Sharp7.Rx.2.0.${{ github.run_number }}-prerelease.nupkg -s https://api.nuget.org/v3/index.json -k ${{ secrets.NUGET_DEPLOY_KEY }}