harcode 11.0 for universal2 installer

osx_utils.sh

@@ -158,7 +158,7 @@ function pyinst_fname_for_version {
     local py_osx_ver=${2:-$(macpython_sdk_for_version $py_version)}
     local inst_ext=$(pyinst_ext_for_version $py_version)
     if [ "${PLAT:-}" == "arm64" ] || [ "${PLAT:-}" == "universal2" ]; then
-      echo "python-${py_version}-macos${py_osx_ver}.${inst_ext}"
+      echo "python-${py_version}-macos11.0.${inst_ext}"
     else
       echo "python-${py_version}-macosx${py_osx_ver}.${inst_ext}"
     fi