Fix alias afk for big sur

See mathiasbynens#946

stow/shell/dot-aliases

@@ -132,7 +132,7 @@ alias stfu="osascript -e 'set volume output muted true'"
 alias pumpitup="osascript -e 'set volume output volume 100'"
 
 # Lock the screen (when going AFK)
-alias afk="/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend"
+alias afk="osascript -e 'tell app \"System Events\" to key code 12 using {control down, command down}'"
 
 # Reload the shell (i.e. invoke as a login shell)
 alias reload="exec ${SHELL} -l"