ci: add github action

Author: CSUwangj

.github/workflows/md2docx.yml

@@ -0,0 +1,33 @@
+name: build new md2docx-csharp
+ 
+on: [push]
+ 
+jobs:
+  build:
+ 
+    runs-on: windows-latest
+ 
+    steps:
+    - uses: actions/checkout@v1
+      name: Checkout Code
+     
+    - name: Setup MSBuild Path
+      uses: warrenbuckley/Setup-MSBuild@v1
+       
+    - name: Setup NuGet
+      uses: NuGet/setup-nuget@v1.0.2
+     
+    - name: Restore NuGet Packages
+      run: nuget restore
+      
+    - name: Test
+      run: dotnet test
+ 
+    - name: Build md2docx-csharp
+      run: MSBuild.exe Solution.sln /p:Configuration=Release /p:Platform="Any CPU"
+ 
+    - name: Upload Artifact
+      uses: actions/upload-artifact@v1.0.0
+      with:
+        name: md2docx
+        path: md2docx\bin\Release