fix README (#48)

Author: mikhailkoliada

README.md

@@ -1,7 +1,7 @@
 # setup-xcode
-This action is intended to switch between pre-installed versions of Xcode for macOS images in GitHub Actions.  
+This action is intended to switch between pre-installed versions of Xcode for macOS images in GitHub Actions.
 
-The list of all available versions can be found in [virtual-environments](https://github.com/actions/virtual-environments/blob/master/images/macos/macos-10.15-Readme.md#xcode) repository.
+The list of all available versions can be found in [runner-images](https://github.com/actions/runner-images/blob/master/images/macos/macos-12-Readme.md#xcode) repository.
 
 # Available parameters
 | Argument                | Description              | Format    |