Revert changes to mac build for now

.appveyor.yml

@@ -1,6 +1,6 @@
 image:
   - Visual Studio 2019
-  - macos-bigsur
+  - macos
 clone_depth: 400
 
 for:
@@ -95,11 +95,10 @@ for:
   -
     matrix:
       only:
-        - image: macos-bigsur
+        - image: macos
     # Should be enabled only for build process debugging
     init:
     #   - sh: curl -sflL 'https://raw.githubusercontent.com/appveyor/ci/master/scripts/enable-ssh.sh' | bash -e -
-      - sh: ls ~
       - sh: source ~/venv3.7/bin/activate
     install:
       - sh: bash scripts/osx-setup.sh