Use old MSBuild to test

Author: LeonBlade

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
           submodules: recursive
 
       - name: Setup MSBuild
-        uses: microsoft/setup-msbuild@v2
+        uses: microsoft/setup-msbuild@v1.0.3
 
       - name: Download Dalamud
         run: |