Add a quick automatic CI build and test

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+
+name: CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v3
+
+    - name: Restore dependencies
+      run: dotnet restore
+
+    - name: Build
+      run: dotnet build --configuration Release
+
+    - name: Test
+      run: dotnet test --configuration Release --no-build

global.json

@@ -0,0 +1,6 @@
+{
+  "sdk": {
+    "version": "8.0.100",
+    "rollForward": "latestPatch"
+  }
+}