add basic .Net build and test GHA workflow

.github/workflows/build-dotnet.yml

@@ -0,0 +1,32 @@
+name: Test Build Plugin
+
+on:
+  push:
+    branches: [ master ]
+    paths-ignore:
+      - "**/*.md"
+  pull_request:
+    branches: [ master ]
+    paths-ignore:
+      - "**/*.md"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: "Setup .NET Core"
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      - name: "Install dependencies"
+        run: dotnet restore
+
+      - name: "Build"
+        run: dotnet build --configuration Release
+
+      - name: "Test"
+        run: dotnet test --no-restore --verbosity normal
+