Fix a broken command

.appveyor.yml

@@ -20,13 +20,11 @@ skip_commits:
     - '**/*.[1-8]'
     - '**/*.ronn'
 environment:
-  ruby_version: "24-%Platform%"
   matrix:
     # We try to test the oldest supported version, however, we need to use
     # Visual Studio 2019 for baseruby >= 2.7.
     # https://www.appveyor.com/docs/windows-images-software/#ruby
     - build: vs
-      vs: 160
       ssl: OpenSSL-v111
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       GEMS_FOR_TEST: ""
@@ -49,10 +47,7 @@ for:
     - .\bootstrap-vcpkg.bat
     - cd %APPVEYOR_BUILD_FOLDER%
     - vcpkg --triplet %Platform%-windows install --x-use-aria2 libffi libyaml readline zlib
-    - CALL SET vcvars=%%^VS%VS%COMNTOOLS^%%..\..\VC\vcvarsall.bat
-    - SET vcvars
-    - '"%vcvars%" %Platform:x64=amd64%'
-    - SET ruby_path=C:\Ruby%ruby_version:-x86=%
+    - call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"
     - SET PATH=\usr\local\bin;%ruby_path%\bin;%PATH%;C:\msys64\mingw64\bin;C:\msys64\usr\bin
     - ruby --version
     - 'cl'
@@ -73,11 +68,11 @@ for:
         if not %%~nI == readline mklink \usr\local\bin\%%~nxI %%I
       )
     - attrib +r /s /d
-    - mkdir %Platform%-mswin_%vs%
+    - mkdir %Platform%-mswin
   build_script:
     - set HAVE_GIT=no
     - cd %APPVEYOR_BUILD_FOLDER%
-    - cd %Platform%-mswin_%vs%
+    - cd %Platform%-mswin
     - >-
       ..\win32\configure.bat
       --with-opt-dir="/usr/local;c:/Tools/vcpkg/installed/%Platform%-windows"