Add GitHub Actions as the CI runner

We are working on consolidating all CI to GitHub Actions.

.github/workflows/ci.yml

@@ -0,0 +1,30 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - 'main'
+  pull_request: {}
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  test:
+    name: Test C# ${{ matrix.dotnet }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        dotnet: [ '3.x', '6.x', '7.x', '8.x' ]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup dotNet
+        uses: actions/setup-dotnet@v3
+        with:
+          dotnet-version: ${{ matrix.dotnet }}
+      - name: Test
+        run: |
+          dotnet build -c Debug src/WorkOS.net/WorkOS.net.csproj
+          dotnet build -c Debug test/WorkOSTests/WorkOSTests.csproj
+          dotnet test -c Debug -f netcoreapp3.1 test/WorkOSTests/WorkOSTests.csproj