Add basic CI

As found out the hard way in #87, currently there are no CI checks to validate that code is even syntactically valid before merging.

This adds a basic build step that verifies that client example (and, by extension, the library itself as it relies on it) builds successfully.

.github/workflows/dotnet.yml

@@ -0,0 +1,25 @@
+# This workflow will build a .NET project
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-net
+
+name: .NET build
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: 7.0.x
+    - name: Build client example
+      run: dotnet build
+      working-directory: examples/quickstart/client