Add GitHub Actions workflow for .NET testing

.github/workflows/main.yml

@@ -0,0 +1,20 @@
+name: Test
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v3
+        with:
+          dotnet-version: 10.0.x
+
+      - name: Test
+        run: dotnet test Tests --verbosity normal