Add pkgutil version for XQuartz 2.7.5_rc4

Library/Homebrew/os/mac/xquartz.rb

@@ -19,6 +19,7 @@ module OS
         "2.7.50" => "2.7.5_rc1",
         "2.7.51" => "2.7.5_rc2",
         "2.7.52" => "2.7.5_rc3",
+        "2.7.53" => "2.7.5_rc4",
       }.freeze
 
       # This returns the version number of XQuartz, not of the upstream X.org.