Setup msbuild action

.github/workflows/msbuild.yml

@@ -0,0 +1,26 @@
+name: MSBuild
+
+on: [push]
+
+env:
+  # Path to the solution file relative to the root of the project.
+  SOLUTION_FILE_PATH: .\tools\msvc\DarkRadiant.sln
+  BUILD_CONFIGURATION: Release
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Add MSBuild to PATH
+      uses: microsoft/setup-msbuild@v1
+
+    #- name: Restore NuGet packages
+    #  working-directory: ${{env.GITHUB_WORKSPACE}}
+    #  run: nuget restore ${{env.SOLUTION_FILE_PATH}}
+
+    - name: Build
+      working-directory: ${{env.GITHUB_WORKSPACE}}
+      run: msbuild /m /p:Configuration=${{env.BUILD_CONFIGURATION}} /p:Platform=x64 ${{env.SOLUTION_FILE_PATH}}