.github: use call

.github/workflows/main.yml

@@ -37,9 +37,7 @@ jobs:
         - name: windows-make-debug64
           shell: cmd
           run: |
-            cd "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build"
-            .\vcvarsall.bat x64
-            cd "D:\a\crown\crown"
+            call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" x64
             cd "3rdparty\luajit\src"
             .\msvcbuild.bat
             cd "D:\a\crown\crown"