Use matrix for building across all platforms

.github/workflows/build.yml

@@ -6,10 +6,16 @@ name: Continuous Integration
 
 jobs:
   test:
-    name: Build for Linux
+    name: Build for ${{ matrix.os }}
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
     runs-on: ubuntu-latest
     timeout-minutes: 10
+    strategy:
+      matrix: 
+        os:
+          - Linux
+          - Windows
+          - MacOS
     steps:
       - name: Cancel previous runs of this workflow
         uses: styfle/cancel-workflow-action@0.6.0
@@ -25,9 +31,9 @@ jobs:
           dotnet-version: "5.0.x"
           
       - name: Compile
-        run: dotnet publish -c Linux
+        run: dotnet publish -c ${{ matrix.os }}
         
       - uses: actions/upload-artifact@v2
         with:
-          name: UnionPatcher-Linux
-          path: ${{ github.workspace }}/UnionPatcher.Gui.Linux/bin
+          name: UnionPatcher-${{ matrix.os }}
+          path: ${{ github.workspace }}/UnionPatcher.Gui.${{ matrix.os }}/bin