Add CI github workflow.

.github/workflows/ci.yml

@@ -0,0 +1,17 @@
+name: CI
+
+on: push
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/setup-dotnet@v3
+      with:
+        dotnet-version: '7.x'
+    - name: Install dependencies
+      run: dotnet restore
+    - name: Build
+      run: dotnet build