Add gh action for building the library and Das app (without tests for…

… now)

.github/workflows/build-and-test.yml

@@ -0,0 +1,38 @@
+name: Build and test
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build-and-test-linux:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup .NET 5
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '5.0.x'
+    - name: Restore local tools
+      run: dotnet tool restore
+    - name: Build and test
+      run: dotnet fake build -t build
+
+  build-and-test-windows:
+
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup .NET 5
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '5.0.x'
+    - name: Restore local tools
+      run: dotnet tool restore
+    - name: Build and test
+      run: dotnet fake build -t build