Run CI on multiple dotnet versions on different os

Author: Havret

.github/workflows/build.yml

@@ -9,27 +9,20 @@ on:
       - main
 
 jobs:
-  linux:
-    runs-on: ubuntu-latest
+  CI:
+    strategy:
+      matrix:
+        os: [macos-latest, windows-latest, ubuntu-latest]
+        dotnet: ['2.1.x', '3.1.x', '5.0.x', '6.0.x']
+    runs-on: ${{ matrix.os }}
+    name: CI on ${{ matrix.os }} using dotnet ${{ matrix.dotnet }}
     steps:
       - uses: actions/checkout@v1
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: "6.0.x"
+          dotnet-version: ${{ matrix.dotnet }}
       - name: Build with dotnet
         run: dotnet build --configuration Release
       - name: Test with dotnet
-        run: dotnet test --configuration Release
-  windows:
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v1
-      - name: Setup .NET Core
-        uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: "6.0.x"
-      - name: Build with dotnet
-        run: dotnet build --configuration Release
-      - name: Test with dotnet
-        run: dotnet test --configuration Release
+        run: dotnet test --configuration Release